Revert "Revert "[CEC Configuration] Add listener support to the HdmiCecConfig""

This reverts commit 906e3ea6.

Failing test was modified to trigger the Settings listener more
reliably. Running the test many iterations did not show any failures
locally.

Bug: 172905515
Test: atest HdmiCecConfigTest --iterations 25

Change-Id: Id81979ef3c38dfa7aa8db3a66a3d23db562bd0ea