[Feature] Mitigation noise should be treated differently from model noise

[rajaiitp]

Currently Mitigation picks device noise if nothing is used. Additionally model picks noise argument from mitigation if no model noise is set.

Expected behavior as follows

• Model noise should be set only via Model
• Mitigation can pick model noise if protocol needs
• Mitigation can use a different noise model from the device noise to do mitigation, very commonly happens on the hardware