[FEATURE] BlockChangeEvent Improvement

[mumy-255]

LiquidBounce Branch

Nextgen

Describe your feature request.

Due to the absence of the 'oldState' in BlockChangeEvent, it has become extremely cumbersome or even impossible to properly implement certain functionalities (such as specific changes in block states).

Please add the 'oldState' field to facilitate the implementation of more related features.

Additional context

No response