Send <Inactive Source> if put to standby by connected device

<Inactive Source> should only be suppressed if followed by a <Standby>
message.

Since no <Standby> is sent by the device if it was put to sleep by a
connected device via CEC, <Inactive Source> should be sent.

Test: atest
Bug: 183603416
Change-Id: Ibb4393c82b5ba7da13983877e1f91172a19f9add
Merged-In: Ibb4393c82b5ba7da13983877e1f91172a19f9add