Fix T90570: Constraint validity not updated with library overrides.

For some reason was assuming setting a property in RNA would call its
update callback if any, but this actually needs to be done separately.

So add this call to `rna_property_override_operation_apply`.

source/blender/makesrna/intern/rna_access_compare_override.c

@@ -614,20 +614,25 @@ static bool rna_property_override_operation_apply(Main *bmain,
   }
 
   /* get and set the default values as appropriate for the various types */
-  return override_apply(bmain,
-                        ptr_dst,
-                        ptr_src,
-                        ptr_storage,
-                        prop_dst,
-                        prop_src,
-                        prop_storage,
-                        len_dst,
-                        len_src,
-                        len_storage,
-                        ptr_item_dst,
-                        ptr_item_src,
-                        ptr_item_storage,
-                        opop);
+  const bool sucess = override_apply(bmain,
+                                     ptr_dst,
+                                     ptr_src,
+                                     ptr_storage,
+                                     prop_dst,
+                                     prop_src,
+                                     prop_storage,
+                                     len_dst,
+                                     len_src,
+                                     len_storage,
+                                     ptr_item_dst,
+                                     ptr_item_src,
+                                     ptr_item_storage,
+                                     opop);
+  if (sucess) {
+    RNA_property_update_main(bmain, NULL, ptr_dst, prop_dst);
+  }
+
+  return sucess;
 }
 
 /**