fixed failed assertion, removed U128

[Thunkar]

Issues found

• There's a problem with AVM bytecode not being properly detected. That's already addressed by fix(avm-simulator): await avm bytecode check AztecProtocol/aztec-packages#8268 (review)
• TXE logs MUST be made available to the user in order for them to debug their own code (via debug_log_format) and also provide us with proper feedback. Tracked by: bug: TXE logs are not made available via aztec test AztecProtocol/aztec-packages#8270
• U128 has custom serialization, and it's basically unusable in anything that's serialized/deserialized across the Noir<->TS barrier, including call interfaces, TXE oracle calls, etc. It's something that's bitten us again and again in the past, generating impossible to debug problems. Until it's fixed (tracked by bug: Change U128 serde to respect "canonical" Noir serde AztecProtocol/aztec-packages#8271), better use Field: WARNING: I have NOT checked the math in this PR, just made it compile
• Finally, the user was trying to do a transfer_public from an address that was not the owner of the funds (VanhelsingContract). In order to do that, they have to use authwits. TXE provides a convenient cheatcode for that.