Describe the bug

Once Adonis is used, MenuItem' hotkeys are not respected (they should be), and the underscore is displayed (it should not be)

To Reproduce

Steps to reproduce the behavior:

• Use a MenuItem with an underscore at the beginning of the Header property string.
• Add Adonis-UI nuget package.

Expected behavior

The same behavior as vanilla WPF.

• Keyboard navigation should work (Alt + F for a MenuItem Header labeled "_File" for example)
• The MenuItem is displayed as "File", not "_File" (true at runtime AND design time)
• At runtime, after a press on the Alt key, all hotkey'd hints should be displayed