Fix database permissions for the Filter extension

[jtherrmann]

With the Filter extension enabled in our public API, an attempt to query the GET /queryables endpoint via the Swagger UI results in a 500 Internal Server Error:

{
  "code": "InsufficientPrivilegeError",
  "description": "permission denied for table queryables"
}

We should fix the database permissions and then re-add filter to the list of enabled extensions.