Disable waitForSampleControl for snapshots tests

Only rely on IsTestDone which is based on test id and cannot race with the previous test and the RunTest backdoor. Reduce retry time for IsTestDone.

src/SamplesApp/SamplesApp.UITests.Generator/SnapShotTestGenerator.cs

@@ -108,7 +108,7 @@ namespace Uno.Samples.UITest.Generator
 							builder.AppendLineInvariant("[SamplesApp.UITests.TestFramework.AutoRetry]");
 							using (builder.BlockInvariant($"public void {Sanitize(test.category)}_{Sanitize(info.name)}()"))
 							{
-								builder.AppendLineInvariant($"Run(\"{test.symbol}\");");
+								builder.AppendLineInvariant($"Run(\"{test.symbol}\", waitForSampleControl: false);");
 							}
 						}
 					}

src/SamplesApp/SamplesApp.UITests/SampleControlUITestBase.cs

@@ -246,7 +246,7 @@ namespace SamplesApp.UITests
 			{
 				var result = _app.InvokeGeneric("browser:SampleRunner|IsTestDone", testRunId).ToString();
 				return bool.TryParse(result, out var testDone) && testDone;
-			}, retryFrequency: TimeSpan.FromMilliseconds(250));
+			}, retryFrequency: TimeSpan.FromMilliseconds(50));
 
 			TakeScreenshot(metadataName.Replace(".", "_"));
 		}