Fix miscellaneous regressions

[OxygenCobalt]

Fixes the following:

• Auth would crash the server since it would still attempt to write first and last names
• Profile view was broken since it used a differently-named first and last name field
• PFP uploads would not work since it would update the incorrect field in user
• Uploading a PFP for the first time would crash the server since it would try to remove uploads/undefined.