Flaky: StopNonInteractiveTests E2E timeouts

The following tests in StopNonInteractiveTests are flaky/timing out on PR CI:

- `Aspire.Cli.EndToEnd.Tests.StopNonInteractiveTests.StopNonInteractiveMultipleAppHostsShowsError` — times out at `WaitUntilText(""AppHost started successfully."")` after 3 minutes (`aspire start` from template-created project).
- `Aspire.Cli.EndToEnd.Tests.StopNonInteractiveTests.StopAllAppHostsFromUnrelatedDirectory` — times out at `WaitUntil(""success prompt [14 OK] $"")` after 8m20s.

These have failed 3 reruns in a row on PR #16636 with different transient failure modes; they appear to be infrastructure/timing flakes in the `aspire new`/`aspire start` E2E flow, not specific to test logic.

Sample failing run: https://github.com/microsoft/aspire/actions/runs/25209936243