manager: Fix incomplete filtering of AMI events.

The global event filtering code was only in one
possible execution path, so not all events were
being properly filtered out if requested. This moves
that into the universal AMI handling code so all
events are properly handled.

Additionally, the CLI listing of disabled events can
also get truncated, so we now print out everything.

ASTERISK-30137 #close

Change-Id: If8c42edcb2abc5158552da7eba2a8ff6b20e1959