Fixes #39477 - Replace enzyme test in ImpersonateIcon with RTL

[kfamilonidis]

Fixes #39477: Replace enzyme test in ImpersonateIcon with RTL

[Lukshio]

Summary

Real improvement over the old snapshot - now tests actual click interactions (open modal, Confirm calls stopImpersonating) via userEvent, instead of a static render snapshot.

Critical (must fix before merge)

• None

Suggestions (should fix)

• The Tooltip mock (Tooltip: ({ children }) => children) drops the tooltip content entirely, so the tooltip text ("You are impersonating another user, click to stop the impersonation...") is no longer covered at all - the old snapshot did verify this text. PR Fixes #39492 - Replace enzyme test in SettingsTable, SettingsCell, SettingsName with RTL #11084 in this same batch (SettingCell/SettingName) mocks Tooltip while preserving content in a data-testid="tooltip-content" node - recommend using that same pattern here so the tooltip copy stays under test.
• Commit message uses Fixes #39477: ... - the documented convention (see develop history, e.g. Fixes #38653 - Fix settings show endpoint) is Fixes #XXXXX - description with a hyphen, not a colon.

Nice to have (optional)

• Consider adding a "Cancel" button test (modal closes without calling stopImpersonating) alongside the existing "Confirm" test, for symmetry.
• The clickable element is a bare <span onClick> with no button role/keyboard handler (pre-existing, not introduced by this PR) - worth a follow-up accessibility ticket, not blocking here.

Checklist gaps

• Tooltip content assertion dropped (see above).
• Commit message hyphen convention.

[kfamilonidis]

@Lukshio I switched the Tooltip mock from ({ children }) => children (which discarded content) to the content-preserving SettingCell pattern: it renders content into a data-testid="tooltip-content" with its children