feat: Message content width

[przemvs]

Description

Changed message content width for 100%, also assets has max-width for 800px;

Screenshots/Screencast (for UI changes)

Checklist

• PR has been self reviewed by the author;
• Hard-to-understand areas of the code have been commented;
• If it is a core feature, unit tests have been added;

Important details for the reviewers

(Delete this section if unnecessary)

• use (x) data
• can be reviewed commit-by-commit
• be sure to look at ...

[V-Gira]

Bye bye --conversation-message-timestamp-width, you won't be missed 👋

[atomrc]

@przemvs let's not merge now (let's wait for the zulu code-freeze) if you don't mind

[codecov]

Codecov Report

Attention: 23 lines in your changes are missing coverage. Please review.

Comparison is base (eb572d2) 45.42% compared to head (b8f359d) 45.39%.
Report is 20 commits behind head on release/q1-2024.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           release/q1-2024   #16533      +/-   ##
===================================================
- Coverage            45.42%   45.39%   -0.03%     
===================================================
  Files                  740      742       +2     
  Lines                24239    24278      +39     
  Branches              5506     5524      +18     
===================================================
+ Hits                 11010    11022      +12     
- Misses               11822    11846      +24     
- Partials              1407     1410       +3