fix: rich text editor [WPB-12089]

[olafsulich]

WPB-12089 [Web] Text formatting via UI in text input field

Description

Features:

• nested lists support

Fixes:

• mentions while editing a message (works with multiple mentions, a mention with spaces, etc.)
• inserting heading (now works like every other button, earlier works only when the text was selected
• remove link and blockquote markdown auto-changing (from markdown string to rich text)
• shred a few pixels shift when clicking the "show formatting" button aka "Aa" button
• increase line height for lists
• change the order of lists (first ordered, then ordered), like on iOS
• adjust the emoji picker position (display it above the button, not on the side)

Other

• lexical v0.21.0

What's missing:

• fixing list styles after pasting (waiting for Feature: Preserve original format after indenting list item facebook/lexical#6949)
• a setting for the disabling auto transformation of markdown to rich text in preview, to be done in a separate PR
• the issue with adding a new paragraph while doing a soft break (Shift + Enter)

  • currently, those two produce the same output, because we're adding a new paragraph every time someone presses Shift + Tab (it's because we can't use only Enter because it sends a message)

    first line 
    second line
    
    fourth line
    

    and

    first line
    
    second line
    
    fourth line
    

Checklist

• mentions the JIRA issue in the PR name (Ex. [WPB-XXXX])
• 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;

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 29.72973% with 52 lines in your changes missing coverage. Please review.

Project coverage is 46.14%. Comparing base (cb737bc) to head (c32c9d9).
Report is 12 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #18520      +/-   ##
==========================================
- Coverage   46.18%   46.14%   -0.05%     
==========================================
  Files         861      865       +4     
  Lines       26593    26654      +61     
  Branches     6022     6033      +11     
==========================================
+ Hits        12283    12299      +16     
- Misses      12770    12815      +45     
  Partials     1540     1540              

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[przemvs]

LGTM!