add UserDecryptionOptions to login response (#3813)

needed for web-v2023.8.2+ compatibility due to the inclusion of the new
trusted device encryption feature. without this change, the web vault
will assume that you don't have a master password set and force you to
set one.

src/api/identity.rs

@@ -280,6 +280,10 @@ async fn _password_login(
         "ResetMasterPassword": false,// TODO: Same as above
         "scope": scope,
         "unofficialServer": true,
+        "UserDecryptionOptions": {
+            "HasMasterPassword": !user.password_hash.is_empty(),
+            "Object": "userDecryptionOptions"
+        },
     });
 
     if let Some(token) = twofactor_token {