Premature closing of execute span in graphql instrumentation

[samriley]

In the case of execute result being a promise, and if there is no responseHook defined endSpan is called too early

opentelemetry-js-contrib/plugins/node/opentelemetry-instrumentation-graphql/src/instrumentation.ts

Lines 248 to 255 in e5a65c6

	if (
	typeof config.responseHook !== 'function' ||
	result === undefined ||
	err
	) {
	endSpan(span, err);
	return;
	}

This is already handled correctly if there is a responseHook defined

opentelemetry-js-contrib/plugins/node/opentelemetry-instrumentation-graphql/src/instrumentation.ts

Lines 257 to 263 in e5a65c6

	if (result.constructor.name === 'Promise') {
	(result as Promise<graphqlTypes.ExecutionResult>).then(resultData => {
	this._executeResponseHook(span, resultData);
	});
	} else {
	this._executeResponseHook(span, result as graphqlTypes.ExecutionResult);
	}