platform: Fix the gid for the theme manager service

It was mismatched with fs_config, resulting in attribution of the
"-1" gid

Change-Id: Ia6d55af0b39f659da2965f9bc0bda0df5c775ba4
Use generic alarm intent.

Change-Id: I52d6bcbec6a3f540842dcbec8d0f5a1e411722c6