fix: reading JSON string from service_usage_monthly

This was hilariously difficult to debug. This isn't the first time an
issue like this occurred; this happens because of a deviation between
mysql and sqlite, where a JSON-typed column in mysql will return as a
native object in queries, whereas a JSON-typed column in sqlite is a
string column and will therefore return as an un-parsed JSON string in
queries.

src/backend/src/routers/drivers/usage.js

@@ -63,8 +63,15 @@ module.exports = eggspress('/drivers/usage', {
         
         let extra_parsed;
         try {
-            extra_parsed = JSON.parse(row.extra);
+            extra_parsed = db.case({
+                mysql: () => row.extra,
+                otherwise: () => JSON.parse(row.extra),
+            })();
         } catch ( e ) {
+            console.log(
+                '\x1B[31;1m error parsing monthly usage extra',
+                row.extra, e,
+            );
             continue;
         }