Draft: rotation-manager: Set prelock_transform when changing rotation on a locked display

If the display is locked and phosh is forcing portrait orientation on the lock screen, calls to phosh_rotation_manager_set_transform should update prelock_transform rather than applying the requested rotation straight away.

Marking this as draft since perhaps another improvement that can be added is removing sensitivity from the rotation quick setting button. Perhaps another property (can-transform?) can be added to PhoshRotationInfo. What do you think?