SilentOpenChest improvements

[crazycat256]

This PR modifies the SilentOpenChest feature.

• When a vanish player opens a chest, he becomes a spectator only for 2 ticks (instead of the whole time the chest is open).
• The player no longer receives packets relating to his gamemode change.

These changes prevent the player from passing through the blocks when opening the chest, and prevent the chest from closing if the player moves.

[LeonMangler]

Thank you for the PR! I have had packet adapters for GAME_STATE_CHANGE and NAMED_ENTITY_SPAWN in the past, and they kept breaking with new minecraft releases. Currently I feel like it may perhaps even make more sense to not use them to increase stability. Either way, the current way the silent open chest feature works is very wonky, and I wish someday there would be an API-only option without temporary gamemodes.