Fix shell commands to use "current" user

To ensure a host test that uses the shell command can run as a secondary
user, the user ID associated with the shell app (which runs as user 0 /
system user) cannot be used to obtain the userId. This commit switches
some commands which are user-sensitive over to using the current user.

Bug: 172934905
Test: atest CtsLocationTimeZoneManagerHostTest (when current user is not
      system user)
Change-Id: Ia0711d32986f6733c26aa220f83dd299c04320b6