Assembly: ignore joints in error (#20253)

Co-authored-by: drwho495 <drwho495555@gmail.com>

src/Mod/Assembly/App/AssemblyObject.cpp

@@ -652,7 +652,7 @@ AssemblyObject::getJoints(bool updateJCS, bool delBadJoints, bool subJoints)
         }
 
         auto* prop = dynamic_cast<App::PropertyBool*>(joint->getPropertyByName("Activated"));
-        if (!prop || !prop->getValue()) {
+        if (joint->isError() || !prop || !prop->getValue()) {
             // Filter grounded joints and deactivated joints.
             continue;
         }