Find Commerce: Searching on product code does not work well

Description

Steps to reproduce

1. Download and install QuickSilver sample site.
2. Install Find.Commerce.
3. Go to admin mode.
4. Trigger the Episerver Find Content Indexing Job.
5. Once the job finishes, go to Catalog UI to search for a product by code (For example: S-1234).

Expected: Return a product/variation (with that code).

Actual: Returns many products/variations. If user tries to search for parts of a code (for example, 1234), the site returns nothing.

Note 1: The fix for this issue requires the site to be reindexed after deploying the fixed version.
Note 2: The fixed search supports prefix search, e.g., you get hits on the products/variants with codes beginning with the search query. It does not necessarily mean that a search for any part of a code returns relevant results.