IonSim should give better error messages when vibrational modes are given in a different order

[kdbarajas]

Example:
# Define the initial density matrix
ρ_axial = thermalstate(axial_mode,6)
ρ_radial = thermalstate(radial_mode,6)
ρ_ions = dm(Ca["D-1/2"] ⊗ Ca["S-1/2"])
ρ_initial = ρ_ions ⊗ ρ_axial ⊗ ρ_radial
returns IonSim: Incompatible basis without further information

Temporary solution is to reorder the vibrational modes density matrix:
ρ_initial = ρ_ions ⊗ ρ_radial ⊗ ρ_axial # Corrects Incompatible basis

IonSim should be able to check for this issue and properly correct for it if the ordering doesn't matter

[marwahaha]

I disagree that IonSim should automatically correct for this. We could improve the error message, like Incompatible basis. Make sure the format is (ion, radial, axial).