Make it possible to get the active span in the GraphQL resolver

[Karibash]

Is your feature request related to a problem? Please describe.

The getActiveSpan() function always returns undefined when used in a GraphQL resolver. This issue arises because @envelop/sentry does not execute the GraphQL resolver within the callback of startSpan.

This means that it's not possible to generate child spans for the spans created by @envelop/sentry. For example, @pothos/tracing-sentry uses getActiveSpan(), but since it can't retrieve an active span, it fails to perform tracing properly.

Describe the solution you'd like

For the sake of simplification, some implementations will be omitted, but it is necessary to execute the GraphQL resolver using setExecuteFn within the callback of startSpan as shown below.

onExecute({ args, executeFn, setExecuteFn }) {
  setExecuteFn(args => {
    return Sentry.startSpan(..., span => {
      return executeFn(args);
    });
  });
}

This is the correct way to handle startSpan as described in Sentry's documentation.