Hubspot cookie data handled incorrectly for user that already has one

[sentry-io]

Sentry Issue: FLAGSMITH-API-51F

HubspotTracker.DoesNotExist: HubspotTracker matching query does not exist.
  File "django/db/models/query.py", line 916, in get_or_create
    return self.get(**kwargs), False
  File "django/db/models/query.py", line 637, in get
    raise self.model.DoesNotExist(

UniqueViolation: duplicate key value violates unique constraint "users_hubspottracker_hubspot_cookie_key"
DETAIL:  Key (hubspot_cookie)=(d4b2f190eb2d2072670294dda413d8e2) already exists.

  File "django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)

IntegrityError: duplicate key value violates unique constraint "users_hubspottracker_hubspot_cookie_key"
DETAIL:  Key (hubspot_cookie)=(d4b2f190eb2d2072670294dda413d8e2) already exists.

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  File "organisations/views.py", line 116, in create
    register_hubspot_tracker(request)
  File "integrations/lead_tracking/hubspot/services.py", line 24, in register_hubspot_tracker
    HubspotTracker.objects.update_or_create(