Depsgraph: Fix wrong ID filtering

Was only using first ID instead of all of them.

Might have been causing issues when updating motion paths of
multiple objects.

Spotted by Jack C, thanks!

source/blender/depsgraph/intern/depsgraph_build.cc

@@ -345,7 +345,7 @@ class DepsgraphFromIDsFilter {
   DepsgraphFromIDsFilter(ID **ids, const int num_ids)
   {
     for (int i = 0; i < num_ids; ++i) {
-      ids_.insert(ids[0]);
+      ids_.insert(ids[i]);
     }
   }