fix(ui-side-nav-bar): show focus ring on selected item

[ToMESSKa]

INSTUI-5078

ISSUE:

• the selected item in SideNavBar (v2) showed no focus ring when focused — the a11y team flagged that users couldn't tell which item was selected/focused

TEST PLAN:

• check the example in the v2 version of the SideNavBar in the 4 different themes
• using the Tab, go through the SideNavBar items, each item should have a visible focus ring including the selected "Dashboard" element

[github-actions]

PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-07-24 09:08 UTC

[github-actions]

Visual regression report

✅ No changes.

Status	Count
Unchanged	32
Changed	0
New	0
Removed	0

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