fix(#29): replace == with MutableText#equals (#30)

replace `==` with `.equals` to check for equality by content, not by
reference. This then properly discards the entity, when rejoining the
server.

src/main/java/dev/rvbsm/fsit/mixin/AreaEffectCloudEntityMixin.java

@@ -19,6 +19,7 @@ public AreaEffectCloudEntityMixin(EntityType<?> type, World world) {
 
 	@Inject(method = "tick", at = @At("TAIL"))
 	private void tick$cleanSit(CallbackInfo ci) {
-		if (this.age > 20 && !this.hasPassengers() && this.getCustomName() == SeatEntity.CUSTOM_NAME) this.discard();
+		if (this.age > 20 && !this.hasPassengers() && this.getCustomName() != null && this.getCustomName().equals(SeatEntity.CUSTOM_NAME))
+			this.discard();
 	}
 }