This is a follow-up to #128363, and fixes up the remaining areas of
the sequencer's code that didn't yet account for slotted actions:
1. Moving strips failed to move their animation with them.
2. Duplicating strips failed to duplicate their animation with them.
3. Deleting strips didn't delete their animation channels with them.
This also takes the opportunity to add depsgraph tagging and
notifiers that were already missing in the pre-slotted-actions
code, for the strip delete and strip paste operators. The absence
of these was making the UI not update and was also causing stale
animation data to get evaluated.
Pull Request: https://projects.blender.org/blender/blender/pulls/128440
f37215d583