**Backport of forgejo/forgejo#11642**
- Deleting attachments are also seen as updating attachments due to the frontend always sending a field to edit the name even if the name didn't change. This was not reflected in the unit tests.
- Refactor the updating attachment logic to be more flexible if a attachment does not exist, because it was just deleted or because someone is being malicious.
- Resolvesforgejo/forgejo#11636
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11642
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>
(cherry picked from commit 8572835160)
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## Release notes
<!--URL:https://codeberg.org/forgejo/forgejo-->
- Bug fixes
- [PR](https://codeberg.org/forgejo/forgejo/pulls/11679): <!--number 11679 --><!--line 0 --><!--description Zml4OiBkb24ndCB0cmlwIGRlbGV0aW5nIGF0dGFjaG1lbnQgd2l0aCBtaXNzaW5nIHBlcm1pc3Npb24gZXJyb3I=-->fix: don't trip deleting attachment with missing permission error<!--description-->
<!--end release-notes-assistant-->
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11679
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
91e3c36c69