Change logging order. (#2323)

This PR is moving the logging to the step before parsing the message.
This will allow us to see the json that is causing parsing errors.

Bug: https://github.com/flutter/flutter/issues/115490
diff --git a/app_dart/lib/src/request_handlers/postsubmit_luci_subscription.dart b/app_dart/lib/src/request_handlers/postsubmit_luci_subscription.dart
index 550dc8c..b98ec3c 100644
--- a/app_dart/lib/src/request_handlers/postsubmit_luci_subscription.dart
+++ b/app_dart/lib/src/request_handlers/postsubmit_luci_subscription.dart
@@ -53,11 +53,11 @@
     BuildPushMessage buildPushMessage;
     try {
       final String decodedData = String.fromCharCodes(base64.decode(data));
-      buildPushMessage = BuildPushMessage.fromJson(json.decode(decodedData) as Map<String, dynamic>);
       log.info('Result message from base64: $decodedData');
+      buildPushMessage = BuildPushMessage.fromJson(json.decode(decodedData) as Map<String, dynamic>);
     } on FormatException {
-      buildPushMessage = BuildPushMessage.fromJson(json.decode(data) as Map<String, dynamic>);
       log.info('Result message: $data');
+      buildPushMessage = BuildPushMessage.fromJson(json.decode(data) as Map<String, dynamic>);
     }
     log.fine(buildPushMessage.userData);
     log.fine('Updating buildId=${buildPushMessage.build?.id} for result=${buildPushMessage.build?.result}');