Pipe current user to InputManagerService

IMS currently doesn't support SystemService lifecycle and doesn't
have callbacks for current user changes.
For per user shortcut handling we need to know what the current user
is. So, pass current user info from WM to IMS temporarily.

Bug: 362473586
Test: manual
Flag: EXEMPT bugfix
Change-Id: I48e6c5ff62909ede06c7d863eea582e590e08011