Type of error field in structlog logger differs from geth, alloy (#1…

…2443)

Cherry pick #12241 into `release/2.61`

Co-authored-by: milen <94537774+taratorio@users.noreply.github.com>
Co-authored-by: Alex Sharov <AskAlexSharov@gmail.com>

eth/tracers/logger/json_stream.go

@@ -127,9 +127,7 @@ func (l *JsonStreamLogger) CaptureState(pc uint64, op vm.OpCode, gas, cost uint6
 	if err != nil {
 		l.stream.WriteMore()
 		l.stream.WriteObjectField("error")
-		l.stream.WriteObjectStart()
-		l.stream.WriteObjectEnd()
-		//l.stream.WriteString(err.Error())
+		l.stream.WriteString(err.Error())
 	}
 	if !l.cfg.DisableStack {
 		l.stream.WriteMore()