Add a 'skip or stall' option to fixed date wait steps.

Currently, if one sets up a wait step in a flow with a fixed end date/time, and someone enters that wait step after the end date/time, the wait step is skipped (see What happens if a lead enters a fixed end date wait step after the end?  )?

It should be preferable to provide a "Skip or Stall if ended" option, so that one could chose the behavior :

• Skip would be the current behavior
• Stall would block the lead there and prevent further steps to happen