Transform: Suppress assert w/ vertex paint

source/blender/editors/transform/transform_conversions.c

@@ -8632,6 +8632,10 @@ void createTransData(bContext *C, TransInfo *t)
 			createTransPaintCurveVerts(C, t);
 			countAndCleanTransDataContainer(t);
 		}
+		/* Mark as initialized if above checks fail. */
+		if (t->data_len_all == -1) {
+			t->data_len_all = 0;
+		}
 	}
 	else {
 		createTransObject(C, t);