GPencil: Fix unreported memory leak for weights

As the total of points was changed before free memory, if the total was lower than before, the remaining points were not released.

source/blender/blenkernel/intern/gpencil.c

@@ -1730,7 +1730,6 @@ bool BKE_gpencil_sample_stroke(bGPDstroke *gps, const float dist, const bool sel
   }
 
   gps->points = new_pt;
-  gps->totpoints = i;
   MEM_freeN(pt); /* original */
 
   if (new_dv) {
@@ -1741,6 +1740,8 @@ bool BKE_gpencil_sample_stroke(bGPDstroke *gps, const float dist, const bool sel
     gps->dvert = new_dv;
   }
 
+  gps->totpoints = i;
+
   gps->flag |= GP_STROKE_RECALC_GEOMETRY;
   gps->tot_triangles = 0;