GPencil: Close Box and Circle primitives with geometry

Before the primitives were closed only with cyclic flag, but this doesn't create geometry for the gap. Now, a new geometry is created using close stroke function to have geometry for sculpt or edit.

source/blender/editors/gpencil/gpencil_primitive.c

@@ -1284,6 +1284,11 @@ static void gpencil_primitive_interaction_end(bContext *C,
     }
   }
 
+  /* Close stroke with geometry */
+  if ((tgpi->type == GP_STROKE_BOX) || (tgpi->type == GP_STROKE_CIRCLE)) {
+    BKE_gpencil_close_stroke(gps);
+  }
+
   DEG_id_tag_update(&tgpi->gpd->id, ID_RECALC_COPY_ON_WRITE);
   DEG_id_tag_update(&tgpi->gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY);