Further cleanup the GetContainerId logic for tests

[danegsta]

Description

Make tests that look for container ID more reliable against slight timing issues in healthy status and container ID being updated.

[Copilot]

Pull Request Overview

This PR refactors container ID retrieval in functional tests to improve reliability by centralizing the wait-for-healthy and container ID check into an async helper.

• Introduces GetContainerIdAsync local functions that await both resource health and the presence of container.id.
• Updates Postgres and MySQL tests to call GetContainerIdAsync instead of manually awaiting health.
• Removes redundant WaitForResourceHealthyAsync calls in each test and consolidates the logic.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/Aspire.Hosting.PostgreSQL.Tests/PostgresFunctionalTests.cs	Replaced manual health waits with GetContainerIdAsync calls
tests/Aspire.Hosting.MySql.Tests/MySqlFunctionalTests.cs	Swapped in GetContainerIdAsync, removed explicit health waits

Comments suppressed due to low confidence (2)

tests/Aspire.Hosting.MySql.Tests/MySqlFunctionalTests.cs:587

• Remove the extra semicolon at the end of this line to avoid redundant syntax.

var phpMyAdminId = await GetContainerIdAsync(rns, "phpmyadmin", cts.Token);;

tests/Aspire.Hosting.MySql.Tests/MySqlFunctionalTests.cs:589

• Consider adding a timeout to WaitAsync (e.g., .WaitAsync(TimeSpan.FromMinutes(1), cts.Token)) to prevent the test from hanging indefinitely and align with the PostgreSQL tests.

await app.StopAsync(cts.Token).WaitAsync(cts.Token);