Assign Sites Page Throws Error

[hudson-newey]

Describe the bug Using the "Assign Sites" menu throws an error when the "Update" button is clicked

To Reproduce Steps to reproduce the behavior:

1. Go to a project (eg. "aaaaaaa" on staging)
2. Click on "Assign Sites"
3. Select some sites
4. Click Update
5. Observe that you get an "Unknown Error" from the client side

Expected behavior A clear and concise description of what you expected to happen.

Screenshots On staging

Desktop:

• OS: Windows 10
• Browser Firefox
• Version 122

Additional Information

When using the dev environment, we get the error: model.getFormDataOnlyAttributes is not a function

[hudson-newey]

Additional related bugs that I found during this issue:

Assigning then unassigning a site (in two submit requests) does not unasssign site

To reproduce:

• Assign a site to a project
• Click the "update" button
• Unassign the site to the project
• Click the "update" button
• Observe that no request was made to remove the site from the project (this can be confirmed by reloading the page)