Missed call LED pulse notification is... missing

When a call is received, the screen lights up and the InCallUI is
shown.  If the call goes unanswered a 'missed call' notification
is left, where the LED should also pulse; this pulsing is to indicate
that a missed call occurred even after the screen turns off.

This re-adds that functionality that was removed in:
54369237 Be more strict about triggering notification lights

Bug: 170735830
Test: atest BuzzBeepBlinkTest
Change-Id: If01e8f595affc874b2c9fee82a48283b6aeaceda