Note to self avatar shows random icon from another conversation

[mahibi]

see #5205 (comment)

[ariedov]

I cannot reproduce the issue because I do not have a long enough conversation list, however, let's consider a different scenario when this could happen:

1. I have set the drawable explicitly without coil (like I do for Note to Self)
2. I scroll long enough and have to load the image with coil now
3. Loading fails
4. The default for coil seems to be just not doing anything, so the previously set image would still be present.

This scenario is very similar to what is being reported and seems reproducible with some code/network tampering.

Suggested fixes:

1. Provide a fallback for coil to display in case of failed loading
2. Set a default image in the ConversationItem.showAvatar before loading anything

The loadFirstLetterAvatar is actually a drawable that is set without using coil, so it could be a sensible default to apply in the ConversationItem.showAvatar. Thoughts @mahibi?

[ariedov]

I spent another minute checking the image loading code, and it does have a fallback, which is not what is getting reported. This seems to leave us with the option to reset the image before loading a new one in the showAvatar method, or I am missing something crucial about how the image is being loaded into the ImageView.

The best way to handle it is to reproduce and debug, all I am doing is guessing...