Merge branch '24780-show-last-updated-or-resolved-in-mr-discussion' into 'master'

resolves updated and resolved status is not showing

## What does this MR do?
This MR fixes #24780 

## Are there points in the code the reviewer needs to double check?
NR

## Why was this MR needed?
This MRs removes some important information as par suggested design in #19797. it restores that information

## Screenshots (if relevant)
**Before:**
![before](/uploads/a93091e783de3e550a07ddbc1fa8085a/before.png)
**After:**
![after](/uploads/ceb7f64a6f20155abcf6ea49d4b8059e/after.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #24780

See merge request !7655

app/views/discussions/_discussion.html.haml

@@ -32,6 +32,7 @@
                 an outdated diff
 
             = time_ago_with_tooltip(discussion.created_at, placement: "bottom", html_class: "note-created-ago")
+          = render "discussions/headline", discussion: discussion
 
         .discussion-body.js-toggle-content{ class: ("hide" unless expanded) }
           - if discussion.diff_discussion? && discussion.diff_file

spec/features/merge_requests/diff_notes_resolve_spec.rb

@@ -201,7 +201,7 @@ feature 'Diff notes resolve', feature: true, js: true do
           expect(first('.line-resolve-btn')['data-original-title']).to eq("Resolved by #{user.name}")
         end
 
-        expect(page).not_to have_content('Last updated')
+        expect(page).to have_content('Last updated')
 
         page.within '.line-resolve-all-container' do
           expect(page).to have_content('0/1 discussion resolved')