Remove export_merge_requests_as_csv feature flag

Removes export_merge_requests_as_csv feature flag
from the codebase and associated specs

app/controllers/projects/merge_requests_controller.rb

@@ -318,8 +318,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
   end
 
   def export_csv
-    return render_404 unless Feature.enabled?(:export_merge_requests_as_csv, project, default_enabled: true)
-
     IssuableExportCsvWorker.perform_async(:merge_request, current_user.id, project.id, finder_options.to_h) # rubocop:disable CodeReuse/Worker
 
     index_path = project_merge_requests_path(project)

app/views/projects/merge_requests/_nav_btns.html.haml

-- if Feature.enabled?(:export_merge_requests_as_csv, @project, default_enabled: true)
-  .btn-group
+.btn-group
   = render 'shared/issuable/csv_export/button', issuable_type: 'merge-requests'
 
 - if @can_bulk_update
@@ -8,5 +7,4 @@
   = link_to new_merge_request_path, class: "gl-button btn btn-success", title: "New merge request" do
     New merge request
 
-  - if Feature.enabled?(:export_merge_requests_as_csv, @project, default_enabled: true)
   = render 'shared/issuable/csv_export/modal', issuable_type: 'merge_requests'

config/feature_flags/development/export_merge_requests_as_csv.yml

----
-name: export_merge_requests_as_csv
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/45130
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/267129
-type: development
-group: group::compliance
-default_enabled: true

doc/user/project/merge_requests/csv_export.md

@@ -6,23 +6,12 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 # Export Merge Requests to CSV **(CORE)**
 
-> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/3619) in GitLab 13.6.
-> - It was [deployed behind a feature flag](../../../administration/feature_flags.md), disabled by default.
-> - Became enabled by default in GitLab 13.6.
-> - It's enabled on GitLab.com.
-> - It's recommended for production use.
-> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#enable-or-disable-export-merge-requests-to-csv). **(CORE ONLY)**
-> - It can be enabled or disabled for a single project.
-
-CAUTION: **Warning:**
-This feature might not be available to you. Check the **version history** note above for details.
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/3619) in GitLab 13.6.
 
 Exporting Merge Requests CSV enables you and your team to export all the data collected from merge requests into a comma-separated values (CSV) file, which stores tabular data in plain text.
 
 To export Merge Requests to CSV, navigate to your **Merge Requests** from the sidebar of a project and click **Export to CSV**.
 
-Exported files are generated asynchronously and delivered as an email attachment upon generation.
-
 ## CSV Output
 
 The following table shows what attributes will be present in the CSV.
@@ -54,28 +43,3 @@ The following table shows what attributes will be present in the CSV.
 
 - Export merge requests to CSV is not available at the Group’s merge request list.
 - As the merge request CSV file is sent as an email attachment, the size is limited to 15MB to ensure successful delivery across a range of email providers. If you need to minimize the size of the file, you can narrow the search before export. For example, you can set up exports of open and closed merge requests in separate files.
-
-### Enable or disable Export Merge Requests to CSV **(CORE ONLY)**
-
-Export merge requests to CSV is under development but ready for production use.
-It is deployed behind a feature flag that is **enabled by default**.
-[GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
-can opt to disable it.
-
-To enable it:
-
-```ruby
-# For the instance
-Feature.enable(:export_merge_requests_as_csv)
-# For a single project
-Feature.enable(:export_merge_requests_as_csv, Project.find(<project id>))
-```
-
-To disable it:
-
-```ruby
-# For the instance
-Feature.disable(:export_merge_requests_as_csv)
-# For a single project
-Feature.disable(:export_merge_requests_as_csv, Project.find(<project id>))
-```

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -1998,10 +1998,6 @@ RSpec.describe Projects::MergeRequestsController do
   describe 'POST export_csv' do
     subject { post :export_csv, params: { namespace_id: project.namespace, project_id: project } }
 
-    before do
-      stub_feature_flags(export_merge_requests_as_csv: project)
-    end
-
     it 'redirects to the merge request index' do
       subject
 
@@ -2014,17 +2010,5 @@ RSpec.describe Projects::MergeRequestsController do
 
       subject
     end
-
-    context 'feature is disabled' do
-      before do
-        stub_feature_flags(export_merge_requests_as_csv: false)
-      end
-
-      it 'expects a 404 response' do
-        subject
-
-        expect(response).to have_gitlab_http_status(:not_found)
-      end
-    end
   end
 end

spec/features/merge_requests/user_exports_as_csv_spec.rb

@@ -9,24 +9,10 @@ RSpec.describe 'Merge Requests > Exports as CSV', :js do
 
   before do
     sign_in(user)
-  end
-
-  subject { page.find('.nav-controls') }
-
-  context 'feature is not enabled' do
-    before do
-      stub_feature_flags(export_merge_requests_as_csv: false)
     visit(project_merge_requests_path(project))
   end
 
-    it { is_expected.not_to have_button('Export as CSV') }
-  end
-
-  context 'feature is enabled for a project' do
-    before do
-      stub_feature_flags(export_merge_requests_as_csv: project)
-      visit(project_merge_requests_path(project))
-    end
+  subject { page.find('.nav-controls') }
 
   it { is_expected.to have_button('Export as CSV') }
 
@@ -42,5 +28,4 @@ RSpec.describe 'Merge Requests > Exports as CSV', :js do
       expect(page).to have_content "It will be emailed to #{user.email} when complete"
     end
   end
-  end
 end