BUG: mass data export is broken

[hotavocado]

Issue:

1. go into an applet with multiple users and export data for all users
2. the loading popup appears but when it's finished, no file is available for download
3. (not shown in video) select all users manually and then hitting the export button gives the same bad result

However, if 1 user is, the file is available for download. See video: loom video

URGENT: This affects all ongoing research studies (HBN, HBN RnB, etc), research assistants are exporting the data several times a week to check on participant progress and provide updates.

[natalia-muzyka]

@hotavocado are you able to open dev console (F12) when you are exporting data and check if it is the same issue I was able to catch before? It seems to be fixed for staging but not yet tested, here: https://app.zenhub.com/workspaces/mindlogger-5e11094d0c26311588da9626/issues/childmindinstitute/mindlogger-backend/1300

And also, if it's possible to check whether you can open the Data tab on mobile app for the same user(or admin) who has broken export because it can be related to the recently reported issue: https://mindlogger.atlassian.net/browse/MIN-24

Thank you!

[hotavocado]

@natalia-muzyka looks like the same error message