Add penalty when mining blocks with falling blocks above them (like gravel/sand)

## Describe your suggestion
A penalty for mining blocks with gravity blocks above them. Baritone could still mine those blocks from the middle if its faster, but the penalty would make it not want to if possible. For example, if there's a 3 block tall stack of gravel, there would be a penalty for mining any one of those blocks except the top one (because it would waste time for them to fall), so the one with the least penalty would be the top one.

## Settings
Adjustable penalty for mining blocks with gravity blocks above them, defaulting to a value that would be roughly equivalent for the time it takes to fall

## Context
When telling baritone to mine gravel or sand, or when just mining normally, it often waits for gravel to fall, wasting time.

## Final checklist
- [x] I know how to properly use check boxes
- [x] I have not used any OwO's or UwU's in this issue.

The issue names no file, test, or entry point; start by tracing Baritone's mining decision and its handling of falling gravel or sand. Verify that blocks with gravity blocks above them receive the intended configurable penalty, that the default reflects falling time, and that mining prefers the top block when possible.

Written by the indexing model from the issue text.