Remove unused essentials.jail perm (EssentialsX#6539)

The `/jail` command is just an alias for `/togglejail`. As such, the
`essentials.jail` permission is never used.

Author: JasonHorkles

Essentials/src/main/resources/plugin.yml

@@ -943,8 +943,6 @@ permissions:
     description: Allows access to the /itemname command with RGB text
   essentials.itemname.prevent-type.<item-name>:
     description: Prevents the player from using the /itemname command with the specified item
-  essentials.jail:
-    description: Allows access to the /jail command
   essentials.jail.exempt:
     description: Prevent a specified group or player from being jailed
   essentials.jail.allow.<command>: