ActivityManagerShellCommand calls getUserSwitchability with wrong user

UserManager.getUserSwitchability API is always called with userId 0
from ActivityManagerShellCommand. This CL fixes that issue by passing
the userId parameter came from the command line to the API.

Bug: 261857907
Test: adb shell am switch-user -w 10
Change-Id: I3d6fa18f63f4b6e01acbf197cfcb5cedb614925c