Some ISkill.CalculateDifficulty() implementations have side effects

[Syriiin]

Some ISkill.CalculateDifficulty() implementations have side effects which would cause a different result to return if called a second time.

eg. Volatility recovery in DimensionalSkill.CalculateEnergyExertion() (which is called from PhysicalSkill.CalculateDifficulty())

UniCircleDifficulty/UniCircle.Difficulty/Skills/Physical/Dimensional/DimensionalSkill.cs

Lines 49 to 51 in 53a048c

	// Recover
	_snapForceVolatility *= 1 - ForceVolatilityRecovery(_deltaTime);
	_actualForceVolatility *= 1 - ForceVolatilityRecovery(_deltaTime);

These lines with side effects should be refactored to be done within ProcessHitObject() instead