Displays mediadrm and Widevine metrics in dumpsys

Make the list of keys in allowedKey to match the
statsd_handlers[] in iface_statsd.cpp for dumpsys
to display mediadrm and Widevine metrics.

Bug: 149246413

Test: adb shell dumpsys media.metrics | grep -i drm
Test: adb shell dumpsys media.metrics | grep -i widevine
Change-Id: I7811eb3a4228a906bb3dbc615ce42d1947082a07