Remove FluentMenu unregister workaround after upstream fix ships

[JamesNK]

Summary

Remove the Aspire dashboard workaround that manually unregisters FluentMenu instances from IMenuService once Microsoft.FluentUI.AspNetCore.Components is updated to a version containing the upstream fix.

Upstream issue: microsoft/fluentui-blazor#5032
Workaround PR: #18853

Context

FluentMenu currently calls IMenuService.Add(this) during initialization but does not remove itself during DisposeAsync(). In long-running dashboard circuits this causes IMenuService to retain disposed menus and the component/data graphs referenced by them.

Aspire works around this by making AspireMenu disposable and extending MobileNavMenu disposal so both manually call IMenuService.Remove(FluentMenu).

Cleanup

Once a Fluent UI dependency version with the fix is available:

• Update Microsoft.FluentUI.AspNetCore.Components to that version.
• Remove the manual IMenuService.Remove calls and related service resolution from AspireMenu and MobileNavMenu.
• Remove or update the workaround-specific component tests.
• Verify disposed menus are still removed with the updated dependency.
• Run the full Aspire.Dashboard.Components.Tests suite.

[joperezr]

🤖 Aspire triage pass — 2026-07-21 23:49 UTC

Area: area-dashboard
Kind: bug (tech-debt cleanup / tracking issue — remove a workaround once an upstream dependency updates)
Repro: none — this is a follow-up cleanup task, not a defect report
Affected version(s): N/A — ongoing until Microsoft.FluentUI.AspNetCore.Components ships the upstream fix; latest Aspire: 13.4.0
Severity: S4 — the underlying menu-retention behavior is already worked around (see PR #18853); no user-facing breakage, purely cleanup

Urgency: ⚪ backlog — no milestone
Reason: S4 cleanup gated on an external dependency bump; not a 13.4 regression, no servicing bar met

Suggested owner(s): @adamint (score 9), backup @mitchdenny (score 3)
Evidence:

• adamint merged Add accessible name to Markdown copy button #18816, Fix Resources accessibility keyboard and reflow paths #17926, Improve mobile navigation and Help dialog accessibility #17927, Fix Manage Data selection accessibility semantics #17928, Improve dashboard dialog and control accessibility states #17929 in area-dashboard (last ~30–45d, incl. one today)
• mitchdenny merged WithTerminal(): per-replica interactive terminal sessions (Aspire side, draft) #17866 in area-dashboard (recent core dashboard work)
• Issue author (JamesNK) is the primary dashboard owner but is excluded as the reporter

Confidence: high
Needs human?: no

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