Fix per-world flight permissions

With the implementation of #6012, there was no permission check done when we re-add flight to user's changing worlds. This broke servers with per-world flight permissions.

Author: JRoy

Essentials/src/main/java/com/earth2me/essentials/EssentialsPlayerListener.java

@@ -778,7 +778,7 @@ public void onPlayerChangedWorldFlyReset(final PlayerChangedWorldEvent event) {
         }
 
         final TickCountProvider tickCountProvider = ess.provider(TickCountProvider.class);
-        if (tickCountProvider != null && user.getFlightTick() == tickCountProvider.getTickCount()) {
+        if (tickCountProvider != null && user.getFlightTick() == tickCountProvider.getTickCount() && user.isAuthorized("essentials.fly")) {
             user.getBase().setAllowFlight(true);
             user.getBase().setFlying(true);
         }