More fixing of flaky UI tests (#3100)

Author: Keboo

MaterialDesignThemes.UITests/WPF/DialogHosts/DialogHostTests.cs

@@ -344,8 +344,10 @@ public async Task DialogHost_WithOpenDialog_ShowsPopupWhenLoaded()
 
         await Wait.For(async () => Assert.True(await closeButton.GetIsVisible()));
 
-        await closeButton.LeftClick();
-
-        await Wait.For(async () => Assert.False(await dialogHost.GetIsOpen()));
+        await Wait.For(async () =>
+        {
+            await closeButton.LeftClick();
+            Assert.False(await dialogHost.GetIsOpen());
+        });
     }
 }

MaterialDesignThemes.UITests/WPF/PasswordBoxes/PasswordBoxTests.cs

@@ -105,6 +105,7 @@ public async Task RevealPasswordBox_WithBoundPasswordProperty_RespectsThreeWayBi
         string? clearTextPassword1 = await clearTextPasswordTextBox.GetProperty<string>(TextBox.TextProperty);
 
         // Act 2 (Update in RevealPasswordTextBox updates PasswordBox and VM)
+        await Task.Delay(50);
         await revealPasswordButton.LeftClick();
         await Task.Delay(50);   // Wait for the "clear text TextBox" to become visible
         await clearTextPasswordTextBox.SendKeyboardInput($"2");