fix(Menu): accessibility for menu when it is first opened

[lukicenturi]

Closes #(issue_number)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 97.56098% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 83.17%. Comparing base (842afa9) to head (24460c3).

Files with missing lines	Patch %	Lines
src/components/overlays/menu/RuiMenu.vue	97.22%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #393      +/-   ##
==========================================
+ Coverage   83.11%   83.17%   +0.05%     
==========================================
  Files          99       99              
  Lines        9008     9044      +36     
  Branches     1344     1353       +9     
==========================================
+ Hits         7487     7522      +35     
- Misses       1521     1522       +1     

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[kelsos]

lgtm