Only attach log files for current test (#17949)

Previously we were attaching all log files in the appium log directory,
so failed tests in AzDO had a large number of attachments, most
unrelated to the test at hand. Fix to only attach files for the current
test.

src/TestUtils/src/UITest.NUnit/UITestBase.cs

@@ -118,13 +118,13 @@ void SaveDiagnosticLogs(string? note = null)
 			{
 				string name = TestContext.CurrentContext.Test.MethodName ?? TestContext.CurrentContext.Test.Name;
 
-				_ = App.Screenshot(Path.Combine(logDir, $"{name}-{_testDevice}{note}ScreenShot"));
-				File.WriteAllText(Path.Combine(logDir, $"{name}-{_testDevice}{note}PageSource.txt"), App.ElementTree);
-			}
+				var screenshotPath = Path.Combine(logDir, $"{name}-{_testDevice}{note}ScreenShot.png");
+				_ = App.Screenshot(screenshotPath);
+				TestContext.AddTestAttachment(screenshotPath, Path.GetFileName(screenshotPath));
 
-			foreach (var log in Directory.GetFiles(logDir))
-			{
-				TestContext.AddTestAttachment(log, Path.GetFileName(log));
+				var pageSourcePath = Path.Combine(logDir, $"{name}-{_testDevice}{note}PageSource.txt");
+				File.WriteAllText(pageSourcePath, App.ElementTree);
+				TestContext.AddTestAttachment(pageSourcePath, Path.GetFileName(pageSourcePath));
 			}
 		}
 	}