Fix carbon ads and nuxt target 'static'

#### Support plan

* *is this issue currently blocking your project?* (yes/no):
* *is this issue affecting a production system?* (yes/no):

#### Context

* *node version*:
* *module version with issue*:
* *last module version without issue*:
* *environment* (e.g. node, browser, native):
* *used with* (e.g. hapi application, another framework, standalone, ...):
* *any other relevant information*:

#### What are you trying to achieve or the steps to reproduce?

```js
const some = 'properly formatted code example';
```

#### What was the result you got?
When building the website using `target: 'static'` in `nuxt.config.js` the carbon ads script tag is not added to the DOM hence ads are not showing up.

#### What result did you expect?
Ads should be displayed. We've removed the `target: 'static'` for now (#438)

Perhaps the problem comes from the `mounted` lifecycle which is not triggered when generating the website statically.