Retrieving records via /api/v1/audit/ with a master API key results in error

Sentry Issue: [FLAGSMITH-API-5GP](https://flagsmith.sentry.io/issues/7211559896/?referrer=github_integration)

```
TypeError: int() argument must be a string, a bytes-like object or a real number, not 'APIKeyUser'
File "django/db/models/fields/__init__.py", line 2053, in get_prep_value
return int(value)

TypeError: Field 'id' expected a number but got .
(19 additional frame(s) were not displayed)
...
File "audit/views.py", line 56, in get_queryset
queryset = AuditLog.objects.filter(q).select_related(
```