task: Ping activity endpoint on user login

[ryanpolasky]

Description

Going to keep this one real short since I'll probably handle this myself, but we need to send a request to the backend at the route /api/auth/activity-ping upon user login. This is just to update the date that the user last signed in. We need to hit this explicitly because the login is handled on the frontend, so this call needs to hit our backend for sake of tracking inactive users.

Note(s)

Research/consider what happens when a user logs in via stored cookie/session & make sure the activity ping still occurs if a user signs in via those methods.