sendOperationHeadersInIntrospection config option, default to true

[mayakoneval]

https://apollograph.slack.com/archives/C021CUR8WCD/p1695311045449899

We need to pass this as a config b/c AS4 defaults to _latest if no one passes a version, and even if we pin a version now, older versions will have changes they don't expect. So we will add a config, default it to the current behavior. Add documentation to encourage folks to make this false & update the default behavior in the hosted Sandbox

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maya-test-embed-next	Configuration