Density guided simulation affine transformation force correction is missing

Summary

Density guided simulation forces are not calculated correctly when using affine transformations with the .mdp option density-guided-simulation-transformation-matrix.

The reason for this error is the missing multiplication with the transpose of the affine transformation matrix to account for the transformation in the forces.

Affects simulations where density-guided-simulation-transformation-matrix is set and not trivial. If the matrices are diagonal, forces are wrongly scaled. If a rotation matrix is set, the effect is a mis-rotation of forces, leading to an overall undesired torque on the structure.