/search genotype empty confusing

In https://dandiarchive.org/search

The dropdown arrow suggests to me that the available options should be displayed in this dropdown view. When no text is entered into the Genotype field, it says "No data available" which suggests to me that this field is not usable.

My suggested solution:

1. Remove the arrow and make this field look like a text field
2. In the empty condition, instead of "No data available" display other more helpful text, e.g. "Enter a genotype"

Open https://dandiarchive.org/search and inspect the Genotype field and its empty-state behavior in the web app. Confirm which frontend files control the dropdown appearance and empty message; it is done when the arrow is removed, the field reads like a text input, and an empty search gives helpful guidance such as “Enter a genotype” instead of “No data available”.

Written by the indexing model from the issue text.