Whitelist MediaProvider for statsd metrics

Now that MediaProvider is a mainline module, we need to whitelist it in
statsd in order to enable pushing metrics from it.

Test: ./out/host/linux-x86/bin/statsd_testdrive -p \
      com.google.android.providers.media.module 233
Fix: 153160314
Bug: 149669087
Change-Id: I5237663de2b24d467283d2c2b60f7155fb5b5e53