Don't send <Report ARC Initiated> until ARC is enabled

Send <Report ARC Initiated> only when ARC is physically enabled.
Currently, this can be sent several seconds early, which violates the
CEC spec.

Currently, when initiating ARC, we do the following in parallel:
1. Query SADs -> Enable ARC
2. Send <Report ARC Initiated>

This CL queries SADs first, to better align the other two tasks:
Query SADs -> | 1. Enable ARC
              | 2. Send <Report ARC Initiated>

Bug: 232241939
Test: manual; atest HdmiCecLocalDeviceTvTest

Change-Id: Ifebc283a8143a7bb48e4cf14ef09090eb1f852fa