Asset conversion nits (#2860)

* [asset-conv] Unused Balances type

* [asset-conv] native asset change

* Dedicated `AssetBalance` type for `pallet_assets` instances

* Improved local vs foreign asset handling + test for not allowing pool_assets in pool

* Removed `into_multiasset_id`

* Fix

* Refactor

* Fixed create_pool for benchmark with LocalAndForeignAssets (finally found it)

* ".git/.scripts/commands/fmt/fmt.sh"

* Revert

* fmt

* Migrates pools with `MultiLocation { parents: 0, interior: Here }` to `MultiLocation { parents: 1, interior: Here }`

* Allow `set_storage` for `AllowMultiAssetPools` / `LiquidityWithdrawalFee`

* Benchmarks work

* Removed comment + more defensive migration

* `T::Currency::transfer` -> `Balances::transfer_all` in migration

* Change pool_id in migration

* Update parachains/runtimes/assets/asset-hub-westend/src/lib.rs

* Bump substrate (manually)

* Bump polkadot

* Fixes from polkadot + clippy

* Fix for xcm-emulator tests (thank you Nacho)

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Co-authored-by: command-bot <>
Co-authored-by: Jegor Sidorenko <[email protected]>