Hybrid store does not support unique actions

[rrennick]

The action scheduler migration gets re-enabled every time a plugin is deactivated. In turn this switches AS to the hybrid data store which does not support unique actions.

I have a dev install that only runs AS actions through CLI that added ~1K copies of a unique action in a couple hours.

1- It should be safe to remove the code that re-enables the hybrid store as the DBStore has been default for almost 4 years.
2- The Hybrid store should support unique actions primarily for development/staging installs

[barryhughes]

It should be safe to remove the code that re-enables the hybrid store as the DBStore has been default for almost 4 years.

For whenever we take this up: let's be careful on this point. Though it was a couple of years back, we did see a relatively popular third party plugin still shipping 2.x (and there could definitely be unmaintained custom plugins in the same boat).

Definitely great if we can do it safely.