[17/n] Handle roundedCorners radius in CommandHandler

Implements the ShellCommandActionHandler to handle the
rounded corners radius options.

The command to run is
adb shell dumpsys activity service SystemUIService WMShell
   letterbox <command>

The commands are:
   cornerRadius <values> - set a new value
   cornerRadius		 - displays current value
   cornerRadiusReset     - resets value to default

Flag: com.android.window.flags.app_compat_refactoring
Bug: 370940685
Test: m and manual

Change-Id: I830d810268b9df7603f4c00929f447f7acf7cdd7