GlucoseUnit is not detected properly

[nielsmaerten]

Describe the bug Reported via Reddit: https://www.reddit.com/r/diabetes/comments/nlt6xj/hey_google_check_my_sugar/gzo60si/?utm_source=reddit&utm_medium=web2x&context=3
I went to check the db, and it turns out there are several users with their Nightscout set to mg/dl, but we have their unit set to mmol/L.

Looks like detection of the glucoseUnit isn't working.
Not sure yet if this is a backend/frontend bug, but I'll enable glucoseUnitField on prod as a temporary fix.

To Reproduce TBD

Expected behavior When signing up with a Nightscout site using mg/dl, the settings in Gluco Check should copy that value

Additional context Adding a hotfix to deal with this by always showing glucoseUnitField, even on prod.