Limit number of queries in batch request

See `Batching Attacks` section: https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/12-API_Testing/01-Testing_GraphQL
> GraphQL supports batching of multiple queries into a single request. This allows users to request multiple objects or multiple instances of objects efficiently. However, an attacker can utilize this functionality in order to perform a batching attack.
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Batching attacks can be used to bypass many security measures enforced on sites. It can also be used to enumerate objects and attempt to brute force multi-factor authentication or other sensitive information.

Currently, you can only enable or disable request batching, but you cannot limit the number of requests in the batch.