Resolve post action shows for other people posts

[FelberMartin]

Describe the bug

In eg a DM or group chat, all users see the "Resolves Post" action when long clicking a thread answer. However clicking this has no effect if the user is not the post author.

To Reproduce
Steps to reproduce the behavior:
I think this should work on any server, course and chat, but here is my setup:

• Login as test_user_1 on TS1
• Interactive Learning WS24/25
• DM chat with test_user_20
• Click test_user_20's post with replies (or create a new reply)
• Long press on the reply
• "Resolves Post" action shows
• Pressing the action does not mark the thread as resolved

Expected behavior
Either pressing the resolve button should resolve the post properly, or the option should not show up in the Actions sheet at all.

Additional context

Investigate how the behaviour is on the webapp (can users mark other user's posts as resolved?) and adjust either the action visibility on Android or fix that clicking "Resolves Post" actually does what its supposed to do.
Maybe it is also important what role the current user has. Eg on the webapp I could observe that test_user_20 (instructor) is able to resolve test_user_1's post in a DM chat.