chore: replace to_radix directive with brillig

[guipublic]

Description

Problem*

Resolves #6302

Summary*

Replace to_radix directive with brillig opcodes

Additional Context

The directive opcode is not removed. It will be removed from AztecPackages once this PR is merged and synced.

This is a draft PR, until the next sync from Aztec Pacakges because it requires AztecProtocol/aztec-packages#9408.

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[TomAFrench]

Looks like we're falling afoul of us needing to know the size of the return type at compile time but we're only passing this in at runtime.

[TomAFrench]

@guipublic I've synced from aztec-packages now.

[TomAFrench]

Looks like this still doesn't work as the linked PR in aztec-packages only handles revert data and not return data.