Delayed and filtered alarms don't trigger

[kasemir]

Found by @tanviash and colleague:

1. Run https://github.com/ControlSystemStudio/phoebus/tree/master/app/alarm/examples/demo.db and associated display.
2. Add the test_alarm PV with enabling filter "test_enable>0" to the alarm tree
3. Use the demo.bob display to test_alarm = 10, it shows up as MAJOR alarm in alarm table and tree
4. Set test_enable to 0. test_alarm is shown in gray with "(disabled)" in alarm tree, and not at all in alarm table
5. Set test_enable back to 1, and test_alarm shows back up as it looked in step 3

Now confiugre the alarm to have a 10 second delay.
It will disable when setting test_enable to 0, but it won't show up as an alarm when test_enable is set back to 1

Fixed in #2309