Changed ordering of matched strings in the dropdown--start of string …

[peterfabian]

…has higher prio.

This pull request includes a

• [ ] Bug fix
• [x] New feature
• [ ] Translation

The following changes were made

• Term searched for by the user is passed down to sorter function, where it's used to sort the matches in a more 'natural' way, e.g. search for term po returns

1. Poland,
2. Portugal
3. and only then French Polynesia.

This should close https://github.com/woocommerce/woocommerce/issues/20575.

I wasn't able to run the tests, though, need to set it up some more...