Due to (optimization) checks in in `BKE_gpencil_prepare_eval_data` &
`BKE_gpencil_update_layer_transforms`, updates were skipped if animation
reached exact identity transforms.
Now check if the matrix has changed additionally to gain proper updates.
Unsure if this is the cheapest way to check for the animated state of
layer transforms tbh, but I see similar checks elsewhere.
Fixes T101164.
Maniphest Tasks: T101164
Differential Revision: https://developer.blender.org/D16018
1cbfe04638