Docs: App bar tweaks to align with v6 & Accessibility

[danielchalmers]

Description

Small tweaks to maintain visual consistency and improve accessibility.

Also fixes Unhandled exception rendering component: Illegal parameter 'Clickable' in component of type 'MudList1'. This was removed in v7.0.0, see Migration Guide for more info

How Has This Been Tested?

visually

Type of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (fix or improvement to the website or code docs)

Horizontal margins around divider were tweaked to restore it back to original style along with the icon being Edge.End.

v6.19.1:

This PR:

Search bar is still not right because of #8878

v7.0.0-preview1:

GitHub icon was removed from drawer because it was ruining alignment from too many icons

v6.19.1:

This PR:

v7.0.0-preview1:

Checklist

• The PR is submitted to the correct branch (dev).
• My code follows the code style of this project.
• I've added relevant tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.11%. Comparing base (28bc599) to head (d3ff495).
Report is 144 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #8879      +/-   ##
==========================================
+ Coverage   89.82%   90.11%   +0.28%     
==========================================
  Files         412      421       +9     
  Lines       11878    12304     +426     
  Branches     2364     2431      +67     
==========================================
+ Hits        10670    11088     +418     
+ Misses        681      666      -15     
- Partials      527      550      +23     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.