Clicking on Series in a Sentry Dashboard Graph Hides the Series instead of Drilling in

### Problem Statement

In a given graph, clicking on a series hides it from the graph instead of showing the series you want to focus on. I believe this is counter intuitive because you want to focus on a series when you click on it. Other graphing services like grafana behave like this as well.

### Solution Brainstorm

Change the behavior from clicking and hiding a series to clicking to drill down into a series. Also support shift + click behavior on multiple series to select a group of them.

### Product Area

Dashboards

The issue names no files, tests, or entry points. Start by locating the Sentry Dashboards graph series-click handler, then confirm the intended single-click drill-down and shift-click multi-series selection behavior; done means clicking focuses a series without hiding it and shift-click can select multiple series.

Written by the indexing model from the issue text.