UI: Allow setting active modifier on linked object

The poll function doesn't apply here because it just checks for object
editability and edit mode, object types, and modifier types. We shouldn't
have a poll function at all because the hovered modifier might not be
part of the context.

Resolves #90008.

Pull Request: https://projects.blender.org/blender/blender/pulls/131384

source/blender/editors/object/object_modifier.cc

@@ -2609,9 +2609,7 @@ void OBJECT_OT_modifier_set_active(wmOperatorType *ot)
 
   ot->invoke = modifier_set_active_invoke;
   ot->exec = modifier_set_active_exec;
-  ot->poll = edit_modifier_liboverride_allowed_poll;
 
-  /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_INTERNAL;
   edit_modifier_properties(ot);
 }