End Portal Flag

**Is your feature request related to a problem? Please describe.**
I have both a survival and creative world on my server. Players in the creative world are able to create end portals which play the portal creation sound to everyone on the server. Perhaps a larger issue is that players who enter portals from the creative world have their survival inventories cleared. I assume this is due to PWI not officially updating to 1.16 yet, and I see denying end portal creation as a temporary solution while I wait for PWI to update.

**Describe the solution you'd like**
I would like a flag that allows me to deny the creation of end portals.

**Describe alternatives you've considered**
I looked at WorldGuardExtraFlags, and that allows me to deny nether portals, but I need to deny the creation of end portals.

Edit: I've disabled the placement of end_portal_frames using WGEF, which should actually solve my issue. I won't close the issue since maybe you still might want to add it. I just don't actually need it anymore.