PlayerMovementInput does incorrect impulse calculation in 1.21.4+

In `PlayerMovementInput.tick()` for sneaking we do:
```java
boolean sneaking = handler.isInputForcedDown(Input.SNEAK);
if (sneaking) {
this.leftImpulse *= 0.3D;
this.forwardImpulse *= 0.3D;
}
```

But in Minecraft 1.21.4+ the sneaking impulse scaling was moved from `ClientInput.tick()` to `LocalPlayer.aiStep()`:
```java
if (this.isMovingSlowly()) {
float f = (float)this.getAttributeValue(Attributes.SNEAKING_SPEED); // default 0.3
this.input.leftImpulse *= f;
this.input.forwardImpulse *= f;
}
```

So when Baritone sneaks we end up with `* 0.3` being applied twice and in servers that use Grim AC you end up constantly failing the simulation check when crouching.

The fix is to just remove the scaling from `PlayerMovementInput.tick()`.
I can do this but just want to know which branches I should cover. I can do all 1.21.4+ branches if needed.

Start in PlayerMovementInput.tick() and compare the sneaking handling with the Minecraft 1.21.4+ behavior described in LocalPlayer.aiStep(). Check the relevant 1.21.4+ branches before making the small change. Done means sneaking impulse is scaled only once and the affected branch behavior no longer applies the duplicate 0.3 multiplier.

Written by the indexing model from the issue text.