Author drop-down on edit form does not prioritise the most likely match

The author dropdown seems to prioritise the least likely match over the most likely match. It's difficult to be certain what someone wants when there are multiple matches, but perhaps prioritising exact match + # of works [and maybe] lower ID will help.

### Evidence / Screenshot (if possible)

Someone adding Charles Dickens almost always will want the senior and not the junior.
### Relevant url?

### Steps to Reproduce

1. Go to ...edit work
2. Do ...add charles dickens to authors

* Actual: The least likely choice is the first option.
* Expected: The most likely choice should be the first option.

### Details

- **Logged in (Y/N)?**
- **Browser type/version?**
- **Operating system?**
- **Environment (prod/dev/local)?** prod

### Proposal & Constraints

### Related files

### Stakeholders

@cdrini

Reproduce the issue through the edit form by adding “Charles Dickens” to the authors field, then locate the author-dropdown implementation and trace how matching authors are ordered. Done means the most likely match appears first, with the behavior verified against the reported senior-versus-junior Dickens case.

Written by the indexing model from the issue text.