setup `pallet-assets-freezer` on testnet asset-hub runtimes
- change(asset-hub-rococo): setup `pallet-assets-freezer`. - change(asset-hub-westend): setup `pallet-assets-freezer`.
- change(asset-hub-rococo): setup `pallet-assets-freezer`. - change(asset-hub-westend): setup `pallet-assets-freezer`.