fix key nav on sidenav

[aalves08]

Summary

Fixes #12780

Occurred changes and/or fixed issues

• Fixes keyboard navigation on the SideNav component
• Update LocaleSelector to remove special implementation on SideNav and reuse the LocaleSelector component

Technical notes summary

Areas or cases that should be tested

Areas which could experience regressions

Screenshot/Video

Screen.Recording.2025-01-21.at.11.44.14.mov

Checklist

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
• The PR has a Milestone
• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes

[rak-phillip]

LGTM - good call on the locale selector!