Function extract_logdata_error 

fn extract_logdata_error(text: &str) -> Option<String>

Parse the LogData receipt before a Revert receipt for logId + discriminant.

In the embedded receipt text, the LogData immediately before the Revert has: LogData { …, rb: , …, data: Some(Bytes()) }

rb identifies the enum type (via ABI loggedTypes). First 8 bytes of data (16 hex chars) is the 0-based variant discriminant.