Add debug statements for why we can't add user to a service on staging

[terrazoon]

Description

When running the app locally, it is possible to add an invited user to a particular service. This fails on staging though, where the admin app cannot find the necessary data in redis that the api app should have provided. The two possibilities seem to be either:

1. redis is broken somehow on staging
2. somehow the redis key is changing on staging (but not locally), so admin can't retrieve what api writes.

Security Considerations

Remove debug statements before this goes to production

[xlorepdarkhelm]

LGTM

[ccostino]

Thanks, @terrazoon!