Unable to upload downloaded form during project creation

[manjitapandey]

Describe the bug
when I create a project with custom/default form and download the form using form download option of project details page. I am not able to upload the same form again during another project creation.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'project details page'
2. Download the xls form
3. Create another project using downloaded xls form
4. See error

Expected behavior
Increase reusability of form during project creation and editing.

Additional context
The same form however works while uploading through form editing page.

[spwoodcock]

The key question here is:

Do we want to expose the final form to the user (including the injected fields), so they can use it themselves manually in ODK?

Or, do we hide all of the FMTM injected fields, so any download of forms always has these fields removed?

(that's the difference you are seeing. Uploading a final form including injected fields will not work currently)

A possible middle ground is to strip these 'FMTM' fields out when uploading the form again (meaning we have to update the logic in osm-fieldwork that handles injecting the fields)