fix(TextBox): Remove FocusRing on macOS

Author: kazo0

src/Uno.UI/UI/Xaml/Controls/PasswordBox/SecureTextBoxView.macOS.cs

@@ -79,6 +79,7 @@ private void Initialize()
 
 			DrawsBackground = false;
 			Bezeled = false;
+			FocusRingType = NSFocusRingType.None;
 		}
 
 		public override CGSize SizeThatFits(CGSize size)

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBoxView.macOS.cs

@@ -115,6 +115,7 @@ private void Initialize()
 
 			DrawsBackground = false;
 			Bezeled = false;
+			FocusRingType = NSFocusRingType.None;
 		}
 
 		public override CGSize SizeThatFits(CGSize size) => IFrameworkElementHelper.SizeThatFits(this, base.SizeThatFits(size));