test(canton): cover EVM transaction param parsing edge cases

[Pessina]

Follow-up from PR #740.

Code:

mpc/chain-signatures/node/src/indexer_canton/contracts.rs

Lines 68 to 73 in 93c8e00

	/// Convert Canton EvmTransactionParams to an alloy TxEip1559.
	///
	/// TODO(test): test address extraction from 32-byte padded hex (Canton format)
	/// vs 20-byte unpadded hex. Test hex parsing of all numeric fields (chain_id,
	/// nonce, gas_limit, fees, value) including edge cases like leading zeros.
	impl TryFrom<&EvmTransactionParams> for TxEip1559 {

Context: EvmTransactionParams accepts Canton-formatted hex values and converts them into TxEip1559. Add tests for 32-byte padded address extraction vs 20-byte unpadded hex, plus numeric parsing for chain_id, nonce, gas_limit, fees, and value, including leading-zero edge cases.