fix(fastify): Make sure consturctor patching works with esm (#1624)

* fix(fastify): Make sure consturctor patching works with esm

* ref: Streamline fastify wrapping

Align this with how other instrumentations wrap.

* Revert "ref: Streamline fastify wrapping"

This reverts commit cbffbc7.

* fix linting

---------

Co-authored-by: Marc Pichler <marc.pichler@dynatrace.com>
Co-authored-by: Amir Blum <amirgiraffe@gmail.com>

plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts

@@ -197,14 +197,14 @@ export class FastifyInstrumentation extends InstrumentationBase {
     };
   }
 
-  private _patchConstructor(
-    original: () => FastifyInstance
-  ): () => FastifyInstance {
+  private _patchConstructor(moduleExports: {
+    fastify: () => FastifyInstance;
+  }): () => FastifyInstance {
     const instrumentation = this;
     this._diag.debug('Patching fastify constructor function');
 
     function fastify(this: FastifyInstance, ...args: any) {
-      const app: FastifyInstance = original.apply(this, args);
+      const app: FastifyInstance = moduleExports.fastify.apply(this, args);
       app.addHook('onRequest', instrumentation._hookOnRequest());
       app.addHook('preHandler', instrumentation._hookPreHandler());