Add Auto Prop Name to 'Delete Color Scheme' button (#15994)

Since the "delete color scheme" button is filled with an icon and a Text
Box, the text is not automatically exposed as the autoProp.Name for the
button. We have to do it manually just like we do for "delete profile".

Validated manually using accessibility insights

Closes #15984

Author: carlos-zamora

src/cascadia/TerminalSettingsEditor/EditColorScheme.cpp

@@ -35,6 +35,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         Automation::AutomationProperties::SetName(RenameAcceptButton(), RS_(L"RenameAccept/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
         Automation::AutomationProperties::SetName(RenameCancelButton(), RS_(L"RenameCancel/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
         Automation::AutomationProperties::SetName(SetAsDefaultButton(), RS_(L"ColorScheme_SetAsDefault/Header"));
+        Automation::AutomationProperties::SetName(DeleteButton(), RS_(L"ColorScheme_DeleteButton/Text"));
     }
 
     void EditColorScheme::OnNavigatedTo(const NavigationEventArgs& e)