Only skip group when it's actually a group in the "Share with group" select

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/controllers/projects/group_links_controller.rb

@@ -7,7 +7,7 @@ class Projects::GroupLinksController < Projects::ApplicationController
     @group_links = project.project_group_links.all
 
     @skip_groups = @group_links.pluck(:group_id)
-    @skip_groups << project.group.try(:id)
+    @skip_groups << project.namespace_id unless project.personal?
   end
 
   def create

changelogs/unreleased/23961-can-t-share-project-with-groups.yml

+---
+title: Only skip group when it's actually a group in the "Share with group" select
+merge_request: 7262
+author: