[automated] Unquarantine stable tests

## Unquarantine Candidates

The following quarantined tests have had 25+ days of quarantined run data with zero failures in the last 25 days, and are candidates for unquarantining.

**Last updated:** 2026-06-30 00:00:52 UTC

### Instructions for Copilot

Use the `test-disabler` agent to unquarantine the tests listed below. For each test:
1. Remove the `[Quarantine]` attribute from the test method
2. Include a `Fixes ` line in the PR description for each tracking issue so they are automatically closed on merge
3. If a test does not have a tracking issue (marked as "None" below), note this in the PR description
4. Validate that all tests listed below have been unquarantined. If any test could not be found or was skipped, call this out in the PR description

**PR requirements:**
- Prefix the PR title with `[automated] `
- Apply the `automated` label to the PR

### Candidates

| Tracking Issue | Oldest Run | Test |
|----------------|------------|------|
| [#8728](https://github.com/microsoft/aspire/issues/8728) | 2026-06-02 | `Aspire.Hosting.Tests.DistributedApplicationTests.ProxylessEndpointWorks` |
| [#15777](https://github.com/microsoft/aspire/issues/15777) | 2026-06-02 | `Aspire.Hosting.Tests.DistributedApplicationTests.StartResourceForcesStart` |

Use the test-disabler agent and locate Aspire.Hosting.Tests.DistributedApplicationTests.ProxylessEndpointWorks and StartResourceForcesStart. First inspect each test's [Quarantine] attribute, then remove it and run the listed tests to confirm they pass without quarantine. Ensure both candidates are handled and record any missing or skipped test in the PR description.

Written by the indexing model from the issue text.