Fix RemoteHost test restore warning in CI

[Copilot]

Description

Main CI failed in the Aspire.Hosting.RemoteHost.Tests Windows job during restore because the Fluent UI preview package emitted NU3027, which CI treats as an error.

• Change
  • Added the existing Fluent UI preview warning suppression to Aspire.Hosting.RemoteHost.Tests, matching other direct consumers of the preview package.

CI SHEPHERD RESULT
status: fixed
summary: Suppressed the known Fluent UI preview package signature warnings for the RemoteHost test project that failed CI restore.
validation: Targeted restore/build and RemoteHost tests passed locally.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No

• Fixes CI failing on main #18608

[Ankit Jain (radical)]

[automated] Ankit Jain (@radical) CI Shepherd handoff: Copilot completed task bf5c47a3… for #18608 and opened this draft PR.

Reported fix: suppress the known Fluent UI preview signature warnings in the RemoteHost test project, matching existing direct consumers. Targeted restore, build, and tests are reported passing; full CI has not yet been observed.

Human action: review the root-cause explanation and proposed suppression, then approve or comment with required changes.