[Feature] Incorporate `campaign_placement_report` into campaign end model

### Is there an existing feature request for this?

- [x] I have searched the existing issues

### Describe the Feature

The connector is currently being updated to include `campaign_id` in the `campaign_placement_report` source table, which means we can easily join this with other `campaign` data here in the package. The placement identifies where the ad is placed -- at the top of the search page, elsewhere in the search page(s), in product or add-to-cart pages, or in Amazon Business? This could help guide marketers on where to best place campaign ads.

### How would you implement this feature?

I suggest bringing this data into the `amazon_ads__campaign_report` model. We could also then aggregate to the account and portfolio level as well, but maybe we start with campaign first.

According to these [docs](https://advertising.amazon.com/help/GYYZVM7LGSRYGWV5), there are 4 possible `placement` classifications (though one is in Beta). To not mess up the grain of the end model(s), I suggest we add metrics for each classification. So something like
```sql
{% for placement in ['list', 'of', 'placement', 'values'] %}
, sum(case when placement = '{{ placement }}' then else 0 end as _{{ placement }}
{% endfor %}
```

This would add quite a few new columns however, so please feel free to push back on anything that doesn't seem valuable

### Describe alternatives you've considered

Don't include placements!

### Are you interested in contributing this feature?

- [ ] Yes.
- [ ] Yes, but I will need assistance.
- [ ] No.

### Anything else?

_No response_