Fly mode unexpectedly active after rejoin #6596

Type of bug

Compatibility issue

/ess dump all output

https://essentialsx.net/dump?bytebin=6C3dDp3669

Error log (if applicable)

No response

Bug description

Interference with other plugins and even with essentials commands cause players to be able to fly after rejoin when they should not.

We have several plugins that alter the game mode of players and the fly state. After rejoining they are now sometimes able to fly when they should not. But this also happens with only essentials and no other plugins involved, see below

Steps to reproduce

Reproduce with essentials itself:
Enable fly mode:
/fly
Go to creative mode:
/gm 1
Go to survival mode:
/gm 0
Now you can not fly.
Rejoin
Now you can fly..

Reproduce with other plugins: Have some plugin that changes game mode or fly mode of players after they typed /fly - same issue

Expected behaviour

fly mode should not be persisted by essentials or at least that feature should be disableable (maybe some permission like essentials.fly.persist or in the config). Having the state of the flying ability in two states - in mc itself and essentials - is just prone to desync between those states and incorrect behaviour

Generaly we do not want players to be flying after joining, we switch gamemode with a plugin to survival when somepone joins, but fly is then sometimes reenabled from essentials

Actual behaviour

Flying players..

Additional Information

Happens since this change: f5fc430