post https://a.klaviyo.com/api/profile-import/
Given a set of profile attributes and optionally an ID, create or update a profile.
Returns 201 if a new profile was created, 200 if an existing profile was updated.
Note that setting a field to null will clear out the field, whereas not including a field in your request will leave it unchanged.
Rate limits:
Burst: 75/s
Steady: 700/m
Scopes:
profiles:write