Currently mutations are being cached in the object cache, and they should not be.

Steps to reproduce:

• activate WPGraphQL Smart Cache
• Under "GraphQL > Settnigs > Cache" enable "Use Object Cache"
• As a public, not-logged-in user, execute a mutation via GraphQL POST request, (like createComment, as shown below)
• Execute the same mutation a 2nd time, and see the response that "This response was not executed at run-time but has been returned from the GraphQL Object Cache"