fix utility::force_batch weight mismatch

[l0r1s]

Description

The returned weights from the pallet_utility::force_batch dispatch is using batch weights instead of its own force_batch causing a weight mismatch log:

2025-10-03 14:57:48 Post dispatch weight is greater than pre dispatch weight. Pre dispatch weight may underestimating the actual weight. Greater post dispatch weight components are ignored.
                                        Pre dispatch weight: Weight { ref_time: 5963137729, proof_size: 3997 },
                                        Post dispatch weight: Weight { ref_time: 5963148560, proof_size: 3997 }    
2025-10-03 14:59:00 Post dispatch weight is greater than pre dispatch weight. Pre dispatch weight may underestimating the actual weight. Greater post dispatch weight components are ignored.
                                        Pre dispatch weight: Weight { ref_time: 2837593294, proof_size: 8703 },
                                        Post dispatch weight: Weight { ref_time: 2837604125, proof_size: 8703 }   

This PR correct the returned weights.

Also created a PR upstream paritytech/polkadot-sdk#9983