Extracts the Clarity error code from a tx_result like: { hex: "0x...", repr: "(err 3)" }
Returns the number (e.g. 3) or null if it's not an (err N).
Optional
Extracts the Clarity error code from a tx_result like: { hex: "0x...", repr: "(err 3)" }
Returns the number (e.g. 3) or null if it's not an (err N).