Known Build Error: Blazor SimpleRunTests/BlazorBuildRunTest Playwright timeout on Counter click

## Build Information
Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1364085
Build error leg or test failing: WBT-NoWebcil-MONO-ST-Wasm.Build.Tests.Blazor.SimpleRunTests
Pull request: https://github.com/dotnet/runtime/pull/126378

## Error Message
```
System.TimeoutException : Timeout 30000ms exceeded.
waiting for Locator("text=Counter")
- waiting for element to be visible, enabled and stable
```

## Build Error Classification
```json
{
"ErrorMessage": "",
"ErrorPattern": "Timeout.*exceeded.*text=Counter.*visible.*enabled.*stable",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
```

## Notes
- Occurs on slow Windows Helix Docker containers where Blazor layout reflows prevent Playwright from considering the Counter nav link "stable" within the default 30s timeout
- Fix in dotnet/runtime#126488: increases timeouts to 60s and adds explicit WaitForAsync(Visible) calls
- Long history of similar Playwright timeout flakes: #94240, #99961, #107865

### Known issue validation
**Build: :mag_right:** https://dev.azure.com/dnceng-public/public/_build/results?buildId=1364085
**Error message validated:** `[Timeout.*exceeded.*text=Counter.*visible.*enabled.*stable`]
**Result validation:** :white_check_mark: Known issue matched with the provided build.
**Validation performed at:** 4/2/2026 8:58:59 PM UTC

### Report
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|0|0|0|