Add "com.android.os.statsd" to libprocessgroup apex_available

The dependency path that determined libprocessgroup is in the
com.android.os.statsd APEX is:

  com.android.os.statsd
    shared lib -> libstatspull
    static lib -> libutils
    shared lib -> libprocessgroup

Bug: 152762638
Test: m droid
Change-Id: Idf5d93085f926cc4fbeba40cbe03684c49baab72