HDMI: Send OTT to standby if user didn't press button on Active Source loss

On active source loss pop-up button press (either Yes or Don't show
again) OTP is triggered. This OTP call cancels the delayed runnable that
will send the device to sleep. The call to assert active source is
redundant and it was removed by this patch to avoid possible regressions
(e.g. remote interference that can lead to focus stealing by the OTT).

Test: atest com.android.server.hdmi
Bug: 376496005
Flag: EXEMPT bugfix
Change-Id: Ifc1f314d200e557a8dffc88fe403f66f89e01496