fix user/auth headers (#836)

One thing to note is that when no `user` is provided, its header does
not appear (as expected). When no `auth` is provided, its header appears
like so:
```
'x-verified-user-data': '{}'
```

plane/src/database/backend.rs

@@ -405,8 +405,8 @@ impl<'a> BackendDatabase<'a> {
             secret_token: SecretToken::from(result.secret_token),
             cluster: ClusterName::from_str(&result.cluster)
                 .map_err(|_| sqlx::Error::Decode("Failed to decode cluster name.".into()))?,
-            user: None,
-            user_data: None,
+            user: result.username,
+            user_data: Some(result.auth),
             subdomain: result
                 .subdomain
                 .map(Subdomain::try_from)