Depsgraph: Introduce ID recalc flag for COW component

Currently unused, but will become handy to check whether ID needs
to have COW update to be run.

source/blender/makesdna/DNA_ID.h

@@ -472,6 +472,7 @@ enum {
 	ID_RECALC_GEOMETRY    = 1 << 4,
 	ID_RECALC_TRANSFORM   = 1 << 5,
 	ID_RECALC_COLLECTIONS = 1 << 6,
+	ID_RECALC_COPY_ON_WRITE = 1 << 7,
 	/* Special flag to check if SOMETHING was changed. */
 	ID_RECALC_ALL   = (~(int)0),
 };