Update group#shared_externally to include projects

Correctly determine if a group or it's subgroups or projects have
been shared externally

Changelog: changed
EE: true

ee/app/models/ee/group.rb

@@ -525,9 +525,17 @@ module EE
 
     def shared_externally?
       strong_memoize(:shared_externally) do
-        invited_group_in_groups
-          .where.not(group_group_links: { shared_with_group_id: ::Group.groups_including_descendants_by([self]) })
-          .limit(1).any?
+        internal_groups = ::Group.groups_including_descendants_by([self])
+
+        group_links = invited_group_in_groups
+          .where.not(group_group_links: { shared_with_group_id: internal_groups })
+          .limit(1)
+
+        project_links = invited_groups_in_projects
+          .where.not(project_group_links: { group_id: internal_groups })
+          .limit(1)
+
+        group_links.any? || project_links.any?
       end
     end
 

ee/spec/models/ee/group_spec.rb

@@ -1577,6 +1577,7 @@ RSpec.describe Group do
     let_it_be(:subgroup_1) { create(:group, parent: group) }
     let_it_be(:subgroup_2) { create(:group, parent: group) }
     let_it_be(:external_group) { create(:group) }
+    let_it_be(:project) { create(:project, group: subgroup_1) }
 
     subject(:shared_externally?) { group.shared_externally? }
 
@@ -1607,6 +1608,18 @@ RSpec.describe Group do
 
       expect(shared_externally?).to be false
     end
+
+    it 'returns true when the group project is shared outside of the namespace hierarchy' do
+      create(:project_group_link, project: project, group: external_group)
+
+      expect(shared_externally?).to be true
+    end
+
+    it 'returns false when the group project is only shared internally within the namespace hierarchy' do
+      create(:project_group_link, project: project, group: subgroup_2)
+
+      expect(shared_externally?).to be false
+    end
   end
 
   it_behaves_like 'can move repository storage' do