Permission classes not properly unmarshalling path arguments

[sentry]

Sentry Issue: FLAGSMITH-API-5GA

ValueError: invalid literal for int() with base 10: 'undefined'
(6 additional frame(s) were not displayed)
...
  File "integrations/github/permissions.py", line 13, in has_permission
    return request.user.belongs_to(organisation_id=int(organisation_id))