Default name for GRAPHQL_ENDPOINT is incorrect

[tytremblay]

https://github.com/aws-amplify/docs/blob/539f79f00c92492a490e28d56aa04a7bb6b36254/src/pages/%5Bplatform%5D/build-a-backend/data/customize-authz/grant-lambda-function-access-to-api/index.mdx?plain=1#L80C172-L80C203

The above line specifies

The default name is amplifyData_GRAPHQL_ENDPOINT unless you have specified a different name in defineData.

When in fact it comes through to the lambda function as AMPLIFY_DATA_GRAPHQL_ENDPOINT