Conditionally change where avatar shows up

[AMoo-Miki]

Description

Reskins the account button and places it in the left nav when updated layout is used:

Also:

• Fixed a TS error
• Added aria-* to the button
• Put a note for contributors to add aria-label and maybe a tooltip

Category

Enhancement

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

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[AMoo-Miki]

The unit-test failures are due to OSD's mock of uiSettings incorrectly doesn't mock the start contract. This is fixed in opensearch-project/OpenSearch-Dashboards#7637.

[derek-ho]

Changes look fine but seems like a unit test is failing

[codecov]

Codecov Report

Attention: Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 71.04%. Comparing base (371495b) to head (044dff1).
Report is 1 commits behind head on main.

Files	Patch %	Lines
public/apps/account/account-nav-button.tsx	40.00%	0 Missing and 3 partials ⚠️
public/apps/account/account-app.tsx	33.33%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2082      +/-   ##
==========================================
- Coverage   71.17%   71.04%   -0.13%     
==========================================
  Files          96       96              
  Lines        2598     2604       +6     
  Branches      387      385       -2     
==========================================
+ Hits         1849     1850       +1     
  Misses        649      649              
- Partials      100      105       +5     

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