New Transaction System Makes the form retrieval bug with the mocks

[aelalamy42]

When using the mocks, the frontend now bugs when trying to retrieve forms.

To recreate this issue, connect to the frontend with mocks and go to the form page. Then, click on any form title and a white screen should appear. If you go in the console, you'll see a type error Because the new Response to that get request is not handled correctly in the frontend.

Therefore, the frontend should be updated so that this new Response structure is taken into account.
Note that this might as well affect other aspects of the system, although no other problem was caught.