Enable `assumeImmutableResults` in ee/app/assets/javascripts/security_configuration/api_fuzzing/graphql/provider.js

Implementation Plan

• Set assumeImmutableResults to true in the Apollo provider that's instantiated in ee/app/assets/javascripts/security_configuration/api_fuzzing/graphql/provider.js.
• Verify that the app is working properly.
• If needed, update the implementation so that the app works with immutable objects (e.g. leverage immer for cache mutations). Doesn't look like we have any resolvers here. As far as I know the places where we need to use immer and immmutable values are in the resolvers. Most of the work here is to verify it works with the flag enabled.