Release 0.71.1

Related to #11914 

* Ignore errors when creating image preview for uploads

* Delete image-specific fields in an uploaded file which cannot be parsed

* Only show a image preview for file upload if format is supported

* Apps: Room’s usernames was not working

* Apps: Allow add members to rooms

[NEW] Add "help wanted" section to Readme

add help wanted section;  made more concise

Closes #12290

[FIX] REST `users.setAvatar` endpoint wasn't allowing update the avatar of other users even with correct permissions (#11431)

* FIx REST users.setAvatar that did not allow to update the avatar of another user even with necessary permission

* Fix users.setAvatar endpoint. Check permission before update avatar

* Add test for not being able to set someone else's avatar

[BREAK] Update `lastMessage` rooms property and convert the "starred" property, to the same format (#12266)

* Update room last message object with reaction, star, pin and snippet

* Add same field format: "starred" in all responses that includes "messages" or "lastMessage" objects

* Add tests cases for message format

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## after
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