Wait for branch protection before removing it

Tests can fail if they try to remove protection from a branch
immediately after the repo was created. This adds a readme so
the repo is created ASAP, and waits for the branch protection
to be applied before removing it.

qa/qa/resource/protected_branch.rb

@@ -72,6 +72,16 @@ module QA
         self.remove_via_api!(&block)
       end
 
+      # Remove the branch protection after confirming that it exists
+      def remove_via_api!
+        Support::Retrier.retry_until(max_duration: 60, sleep_interval: 1, message: "Waiting for branch #{branch_name} to be protected") do
+          # We confirm it exists before removal because there's no creation event when the default branch is automatically protected by GitLab itself, and there's a slight delay between creating the repo and protecting the default branch
+          exists?
+        end
+
+        super
+      end
+
       def api_get_path
         "/projects/#{project.id}/protected_branches/#{branch_name}"
       end

qa/qa/specs/features/ee/browser_ui/3_create/repository/code_owners_with_protected_branch_and_squashed_commits_spec.rb

@@ -4,7 +4,9 @@ module QA
   RSpec.describe 'Create', :requires_admin do
     describe 'Setup an MR with codeowners file' do
       let(:project) do
-        Resource::Project.fabricate_via_api!
+        Resource::Project.fabricate_via_api! do |project|
+          project.initialize_with_readme = true
+        end
       end
 
       let!(:target) do