Make field "manufacturer AID" not searchable

The manufacturer ID fields seems to hit pretty hard in the search and some products have ambiguous values. E.g. a shoe has "jeans" in the manufacturer ID.

generally, fields that are not visible in the webshop should not be searchable. https://demo.commercetools.com/en/search?q=jeans

Start by reproducing the linked search for “jeans” and inspect how the manufacturer AID field is included in the product search data. Check whether other non-visible fields are also searchable. Done means manufacturer AID no longer affects search results while fields visible in the webshop remain searchable.

Written by the indexing model from the issue text.