Fixed elytra fly bounce recasting when any living entity stops gliding

[dekrom]

Type of change

• Bug fix
• New feature

Description

LivingEntityMixin#recastOnLand is injected into isFallFlying, which every LivingEntity
calls, but it has no check that the entity is the local player. isGlidingHook right above it
does exactly that check.

So when any remote player or mob stops gliding, the injection calls
Bounce.recastElytra(mc.player), which sends a START_FALL_FLYING for you, and then feeds
that result back as the other entity's isFallFlying return value with
cir.setReturnValue(...).

Adding the same guard the rest of the file uses keeps the recast on the local player where it
belongs.

Related issues

None that I found.

How Has This Been Tested?

Not reproduced in game yet, this is a missing guard rather than something I caught happening.
isFallFlying runs for every living entity and the injection above it already guards on
mc.player. Builds clean against current master.

Checklist:

• My code follows the style guidelines of this project.
• I have added comments to my code in more complex areas.
• I have tested the code in both development and production environments.