R1:e99c1974b027

Fix the "Add Query to Dashboard..." flow from "Use Results" on search result pages

Summary:
Depends on D20413. Ref T13272. When you search for stuff, you can "Use Results > Add to Dashboard" to generate a query panel.

This needs some updating after the recent refactoring. All the changes are pretty straightforward. Swaps a giant `<select />` for a tokenizer with a datasource.

Test Plan: Used the "Use Results > Add to Dashboard" flow to create a panel on a dashboard using a query.

Reviewers: amckinley…