`request` method of other library is picked up by `http` instrumentation

During https://github.com/elastic/apm-agent-nodejs/issues/1781 I also stumbled over the following behavior:

When wrapping a function called `request` the `http` instrumentation seems to get triggered:

```js
var originalRequest = prisma.fetcher.request
var newRequest = async function(object) {
var span = apm.startSpan('Query Engine (prisma.fetcher.request)')
var result = await originalRequest.call(this, object)
span.end()
return result
}
prisma.fetcher.request = newRequest
```

leads to this debug output:

```
no active transaction found - cannot build new span
intercepted call to http.request { id: null }
```

and quite some confusion.

The workaround or solution is to configure the instrumentation to ignore `http`: `disableInstrumentations: ['http']` in `apm.start()`.