Substrate codesplitting breaks address decoding & user rendering

[jnaviask]

Description

See https://commonwealth.im/edgeware/discussion/5374-pallet_supersig-joint-funding-proposal-with-w3f -- note that the error thrown is likely due to a missing this.polkadot import rather than the address being properly invalid.

Acceptance Criteria

• Substrate address decoding works = user component renders properly, while maintaining code splitting.

[jnaviask]

Related to #2712