Animation: Sensible frame range for motion paths

Motion paths can now be initialised to more sensible frame ranges,
rather than simply 1-250:

    - Scene Frame Range
    - Selected Keyframes
    - All Keyframes

Reviewed By: sybren, looch, dfelinto, pablico

Maniphest Tasks: T93047

Differential Revision: https://developer.blender.org/D13687

source/blender/blenkernel/intern/anim_visualization.c

@@ -153,6 +153,8 @@ bMotionPath *animviz_verify_motionpaths(ReportList *reports,
     if ((mpath->start_frame != mpath->end_frame) && (mpath->length > 0)) {
       /* outer check ensures that we have some curve data for this path */
       if (mpath->length == expected_length) {
+        mpath->start_frame = avs->path_sf;
+        mpath->end_frame = avs->path_ef;
         /* return/use this as it is already valid length */
         return mpath;
       }