Explicitly allow passing either null or fake players to block breaking method extensions

[thecatcore]

Methods handling mining level and mining speed require passing a Player.
Allowing explicitly for either null or fake players would make implementing block breaker or miner logic more easily.
Edit: currently it doesn't crash, but because this isn't an explicit behavior it might cause issues in mods wanting to change the default behavior.

[calmilamsy]

Fake players would be hugely preferred from a server grief prevention/custom mod interaction standpoint, though I already know that's going to be more work.