feat(kusama-asset-hub): Add ability to force to use ChargeAssetTxPayment

[satoshiotomakan]

This pull request refactors how fee asset IDs are handled in the Polkadot signing flow, introducing a new FeeAssetId enum to distinguish between native and asset-based transaction fees. It also adds support for using the ChargeAssetTxPayment extension when paying transaction tips with the native chain token, based on a new proto field. These changes improve code clarity and flexibility for fee payments.

Fee asset handling improvements

• Introduced the FeeAssetId enum to represent either a native token or a specific asset for transaction fees, replacing the previous usage of a raw u32 type. This change affects both the context struct and related functions.
• Updated the fee_asset_id_from_tw function to return a FeeAssetId instead of a u32, and added logic to support charging native fees as assets when the new proto field is set.

Transaction payment extension logic

• Modified the logic in PolkadotEntry to use ChargeAssetTxPayment with the correct asset ID type, utilizing the new as_u32() method of FeeAssetId.

Protocol buffer changes

• Added the charge_native_as_asset_tx_payment boolean field to the SigningInput proto message to control whether native token tips are paid using the asset extension.

[github-actions]

Binary size comparison

➡️ aarch64-apple-ios: 14.18 MB

➡️ aarch64-apple-ios-sim: 14.18 MB

➡️ aarch64-linux-android:

- 18.67 MB
+ 18.67 MB 	 +1 KB

➡️ armv7-linux-androideabi: 15.61 MB

➡️ wasm32-unknown-emscripten: 13.31 MB