NXD: disable licence_key

All repositories which has LICENCE file are failling (see log bellow).
We disabled it for now as it's not mandatory.

Completed 500 Internal Server Error in 10240ms (ActiveRecord: 124.9ms | Elasticsearch: 0.0ms | Allocations: 274932)

ActionView::Template::Error (4:Deadline Exceeded.):
 17:
 18: - if is_project_overview
 19: .project-buttons.gl-mb-3.js-show-on-project-root
 20: = render 'stat_anchor_list', anchors: @project.statistics_buttons(show_auto_devops_callout: show_auto_devops_callout), project_buttons: true
 21:
 22: #js-tree-list{ data: vue_file_list_data(project, ref) }
 23: - if can_edit_tree?

lib/gitlab/git/wraps_gitaly_errors.rb:13:in `rescue in wrapped_gitaly_errors'
lib/gitlab/git/wraps_gitaly_errors.rb:6:in `wrapped_gitaly_errors'
lib/gitlab/git/repository.rb:763:in `license_short_name'
app/models/repository.rb:622:in `license_key'
...

app/models/repository.rb

@@ -617,6 +617,7 @@ class Repository
   cache_method :license_blob
 
   def license_key
+    return
     return unless exists?
 
     raw_repository.license_short_name

[Jérome Perrin]

We can add in commit message:

This is workaround for https://gitlab.com/gitlab-org/gitlab/-/issues/345693