Gitlab::Search::AbuseDetection refactor ALLOWED_SCOPES

Background

Follow up from !155516 (merged)

Gitlab::Search::AbuseDetection has an ALLOWED_SCOPES constant used to determine if a scope is allowed. This is a duplicate list that makes it harder to add new scopes.

Proposal

The abusive scopes should use the existing locations for defining scopes to determine if they are allowed:

app/services/search/global_service.rb app/services/search/project_service.rb ee/app/services/ee/search/global_service.rb ee/app/services/ee/search/group_service.rb

1. Create class methods to expose the allowed_scopes to concatenate them all for abuse detection.

2. Update Advanced search developer documentation to remove abuse detection update from instructions on how to add new scopes