Move Arc notification into lock.

Bug: 366350787
Flag: EXEMPT lock fix
Test: adb -s CAB36A2EE24208000724 shell dumpsys media.audio_flinger | grep AUDIO_DEVICE_OUT_HDMI_ -A 100 | grep AUDIO_FORMAT| grep -v 'AUDIO_FORMAT_PCM'
or
check the Profiles under Port Id: xx "HDMI ARC" under Available Out Devices in dumpsys
and
local test the audio output
Change-Id: I47ec5423f9f550fa18006503be0786f79822965a