Bug: CartesianSamplingOp for different traj along other

[ckolbPTB]

I think this code breaks if we have a different trajectory for other dimensions, because we broadcast along (... other coil):

mrpro/src/mrpro/operators/_CartesianSamplingOp.py

Line 121 in 14b83b2

y_2d = rearrange(y, '... k2 k1 k0 -> (...) (k2 k1 k0)')

Not sure if this can be easily fixed or if it requires a diffferent approach to how we handle the sorting here.