Add attributes for visual indicators on imported items

What does this MR do and why?

This MR is an integration MR between backend and frontend. It passes data via data attributes / helpers / GraphQL from backend to frontend so the "Imported" badge / text is rendered properly.

This is done for Issues, MRs, Epics, Designs, Snippets, Notes (comments / system notes), User profile activity.

Changelog: changed

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshots can be found in each MR listed here: #443492 (comment 1889447118).

⚠️⚠️⚠️ Note: The screenshots below are taken with the diff in !152496 (merged) applied to force show the UI. In reality, not all elements are marked as "Imported" - only the ones which actually are.

Page	Screenshot
Issue
Epic
MR
Design
Snippet
User profile

How to set up and validate locally

Apply this diff to show the "Imported" badge / text:

diff --git a/app/models/concerns/import/has_import_source.rb b/app/models/concerns/import/has_import_source.rb
index f617c7accc38..e8a3fad67b93 100644
--- a/app/models/concerns/import/has_import_source.rb
+++ b/app/models/concerns/import/has_import_source.rb
@@ -23,6 +23,7 @@ module HasImportSource
     end
 
     def imported?
+      return true
       !imported_from_none?
     end
   end

Page	Example URL
Issue	http://127.0.0.1:3000/gitlab-org/gitlab-test/-/issues/49/
Epic	http://127.0.0.1:3000/groups/flightjs/copy/gitlab-instance-2/-/epics/5
MR	http://127.0.0.1:3000/gitlab-org/gitlab-test/-/merge_requests/6
Design	http://127.0.0.1:3000/gitlab-org/gitlab-test/-/issues/49/designs/Screenshot_2024-05-08_at_21.42.46.png
Snippet	http://127.0.0.1:3000/gitlab-org/gitlab-test/-/snippets/21
User profile	http://127.0.0.1:3000/root

Related to #443492 (closed)