feat: Add backend server emoji limit

[Dadadah]

Add the backend limit for server emojis.

Useful for self host.

Partially addresses #1133

How was this PR tested?

Set emoji limit to 1000 in my self host

Screenshots & Screencasts (if appropriate)

Checklist:

• I have carefully read the contributing guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR
• I have confirmed that any new dependencies are strictly necessary
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code

Please declare, if any, LLM usage involved in creating this PR

None

• main
  • feat: Add backend server emoji limit #1312 👈

[Pecacheu]

I would recommend against merging this, cause the means for pulling limits from the backend is standardized in #999 which will ensure that any reactivity happens in perfect sync when the instance changes.