Bugfix: Fix profile picture flickering when sending post

[FelberMartin]

Problem Description

After the introduction of the profile pictures in posts, there has been a bug where the profile picture would flicker when the user sends a new message (post or answer). Originally I thought this bug was related to the posts being falsely recomposed, so I looked into the recomposition of the posts and LazyColumns. While I found some optimizations on the way, the core issue turned out to not being related to recomposition at all (see changes section).

This closes #203

Changes

• Bugfix: pass the author's imageUrl when first locally creating the post before sending it to the server.
• Optimizations done on the way:
  • Use the default coil memoryCacheKey instead of defining it manually
  • Mark post interfaces as @Stable for compose optimizations. (All implementations of these interfaces are data classes and only used in a stable manner). This allows compose to skip recompositions more often
  • Moved the notification payload examples to a different directory as there where compilation problems

Steps for testing

User an account with a profile picture, do:

• Go to any chat (or thread)
• Send a new message
• -> Notice that the profile picture no longer flickers 🥳

[julian-wls]

Really nice change, good catch!
Just tested it and the flickering seems to be gone