Check that all actions have completed before fpt run terminates an applied policy

[douglaswth]

Currently, when fpt run executes without the -k/--keep flag, it does not check if the actions triggered by any incidents have completed before terminating the applied policy.

This can lead to some confusing issues, such as a signer being deleted before an action tries to use it to make an HTTP call.

This should be doable by polling the ActionStatus index for the applied policy ID.