Fix Partner file upload (the one on the partner record)

[cielf]

Summary

The file upload on the partner (not the partner profile) isn't working properly. Fix it.

Why?

It's broken!

Details

To recreate:
Sign in as org_admin1@example.com
click on Partner Agencies | All Partners
click on partner
click on Edit Partner Information (not Edit Profile)
on this page, near the bottom, there is a Documents filed
Choose a file
Update partner

if you go back in to Edit Partner Information, you do not see the file you uploaded

Also, this should appear on the partner view. (It looks to me like we have a partial that appears if and only if the file is present).

Criteria for completion

• documents can be uploaded and viewed on the partner
• automated tests that confirm this behaviour