Lower ReadScriptLogLineAsync cap below per-test xUnit timeout

The internal `CancelAfter` cap was 15s, exactly equal to the
`[SkippableFact(Timeout = 15000)]` on `CanAttachScriptWithPathMappings`.
Because xUnit's per-test timer covers the whole test -- attach,
setBreakpoints, configurationDone and waiting for stopped events all run
before `ReadScriptLogLineAsync` is even entered -- xUnit's generic
timeout would almost always fire first, so the descriptive
`TimeoutException` naming the log path would never surface for the very
test that motivated it.

Drop the cap to 10s so the clearer message can win for that test, while
still bounding the untimed `[Fact]` callers. Per review feedback from
copilot-pull-request-reviewer on #2318.

Drafted by Copilot (Claude Opus 4.8).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: andyleejordan

test/PowerShellEditorServices.Test.E2E/DebugAdapterProtocolMessageTests.cs

@@ -225,8 +225,11 @@ private async Task<string> ReadScriptLogLineAsync(CancellationToken cancellation
             // the test fails fast with a clear message instead of spinning
             // forever -- a busy-spin here previously pegged the CPU and starved
             // xUnit's cooperative test timeout, hanging CI for the full six hours.
+            // Keep this cap meaningfully below the tightest per-test xUnit
+            // `Timeout` (15s on `CanAttachScriptWithPathMappings`) so this
+            // descriptive message wins instead of xUnit's generic timeout.
             using CancellationTokenSource timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
-            timeoutCts.CancelAfter(TimeSpan.FromSeconds(15));
+            timeoutCts.CancelAfter(TimeSpan.FromSeconds(10));
             CancellationToken token = timeoutCts.Token;
 
             try