Missing badge merged in branch list
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### Summary
The "merged" badge is no longer shown in branch list
### Steps to reproduce
Create a branch, merge it into main branch.
### Example Project
### What is the current _bug_ behavior?
The "merged" badge is not shown. If you click the "delete merged branches" button the branch is correctly deleted
### What is the expected _correct_ behavior?
The "merged" badge is shown inside branches list
### Relevant logs and/or screenshots
Branch inside branches list without "merged" badge

<!-- Paste any relevant logs - please use code blocks (```) to format console output, logs, and code
as it's tough to read otherwise. -->
### Output of checks
Api call that shows branch is already merged
`{
"name": "dbt/fix_webapp",
"commit": {
"id": "b7f05311749b469b381895bfe8580d6b7cb73b03",
"short_id": "b7f05311",
"created_at": "2023-06-05T13:26:21.000+00:00",
"parent_ids": [
"68e13d6473f9e6d881dbec54ef5bddceb45dd2d2",
"dc70b443909968e21030fc4c8f92b60cba51ecc9"
],
"title": "Merge branch 'release/0.0.109' into 'dbt/fix_webapp'",
"message": "Merge branch 'release/0.0.109' into 'dbt/fix_webapp'\n\n# Conflicts:\n# dbt/macros/incremental_template_pd.sql",
"author_name": "Daniele Pirola",
"author_email": "daniele.pirola@icteam.it",
"authored_date": "2023-06-05T13:26:21.000+00:00",
"committer_name": "Daniele Pirola",
"committer_email": "daniele.pirola@icteam.it",
"committed_date": "2023-06-05T13:26:21.000+00:00",
"trailers": {},
"web_url": "https://gitlab.com/italiaonline/devops/dataops/-/commit/b7f05311749b469b381895bfe8580d6b7cb73b03"
},
"merged": true,
"protected": false,
"developers_can_push": false,
"developers_can_merge": false,
"can_push": true,
"default": false,
"web_url": "https://gitlab.com/italiaonline/devops/dataops/-/tree/dbt/fix_webapp"
}`
This bug happens on GitLab.com
#### Results of GitLab environment info
<!-- Input any relevant GitLab environment information if needed. -->
<details>
<summary>Expand for output related to GitLab environment info</summary>
<pre>
(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)
(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)
</pre>
</details>
#### Results of GitLab application Check
<!-- Input any relevant GitLab application check information if needed. -->
<details>
<summary>Expand for output related to the GitLab application check</summary>
<pre>
(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:check SANITIZE=true`)
(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true`)
(we will only investigate if the tests are passing)
</pre>
</details>
### Possible fixes
> We removed merged label because it was confusing for users: #385571 (closed). It was replaced with a status of the merge request related to this branch. If the merge request was merged, then the branch is merged.
Blocked because the current way of calculating whether a branch was merged or not would include the scenario of an empty branch scenario https://gitlab.com/gitlab-org/gitlab/-/issues/414845#note_1480740290.
However some users may be ok with mis-information than no information https://gitlab.com/gitlab-org/gitlab/-/issues/414845#note_1484802687
> I understand that show an incorrect information is not so good but it's better than have no informations
issue