Erroneous derivatives of Kraus operators

Functions `CalcMetricTensor` and `CalcExpecPauliStringDerivs` are possibly mishandling arbitrarily parameterised Kraus maps. For example, `Deph[x]` and `Kraus[{ Sqrt[1 - x] IdentityMatrix[2], Sqrt[x] PauliMatrix[3]}]` admit different values from 
```
CalcMetricTensor[InitPlusState @ CreateDensityQureg[1], OP, {x -> .4}]
```
will differ. Check!