Enable linear MembersFinder ancestors queries

In this commit, we're removing the feature flag
`linear_members_finder_ancestor_scopes` to allow
MembersFinder using linear queries.

Changelog: added

app/finders/members_finder.rb

@@ -70,16 +70,11 @@ class MembersFinder
   end
 
   def project_invited_groups
-    invited_groups_and_ancestors = if ::Feature.enabled?(:linear_members_finder_ancestor_scopes, current_user, default_enabled: :yaml)
-                                     project.invited_groups
-                                       .self_and_ancestors
-                                   else
-                                     Gitlab::ObjectHierarchy
-                                       .new(project.invited_groups)
-                                       .base_and_ancestors
-                                   end
-
-    invited_groups_ids_including_ancestors = invited_groups_and_ancestors.public_or_visible_to_user(current_user).select(:id)
+    invited_groups_ids_including_ancestors = project
+                                               .invited_groups
+                                               .self_and_ancestors
+                                               .public_or_visible_to_user(current_user)
+                                               .select(:id)
 
     GroupMember.with_source_id(invited_groups_ids_including_ancestors).non_minimal_access
   end

config/feature_flags/development/linear_members_finder_ancestor_scopes.yml

----
-name: linear_members_finder_ancestor_scopes
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/70583
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/341347
-milestone: '14.4'
-type: development
-group: group::access
-default_enabled: false

spec/finders/members_finder_spec.rb

@@ -202,13 +202,5 @@ RSpec.describe MembersFinder, '#execute' do
     end
 
     it_behaves_like 'with invited_groups param'
-
-    context 'when feature flag :linear_members_finder_ancestor_scopes is disabled' do
-      before do
-        stub_feature_flags(linear_members_finder_ancestor_scopes: false)
-      end
-
-      it_behaves_like 'with invited_groups param'
-    end
   end
 end