Touch devices can pull the vertical indicator off the end of the chart

[krivard]

Actual Behavior:

On touch devices, the vertical indicator is manipulated by dragging. It is possible to drag the indicator to the right beyond the latest available value. This is not possible on devices which use mouseover to manipulate the vertical indicator.

Steps to Reproduce the Bug:

1. go to https://delphi.cmu.edu/covidcast/ on desktop
2. scroll to chart
3. mouseover all the way to the right; final value appears in United States box below
4. go to https://delphi.cmu.edu/covidcast/ on mobile
5. scroll to chart
6. drag all the way to the right; NA appears in United States box below

Expected behavior

vertical indicator should stop at final value available

Screenshots

Rating Scale (1 is minor, 7 is severe): 2 cosmetic, nonmatching

Context

• Desktop Browser: Chrome Version 107.0.5304.87 (Official Build) (arm64)
• Mobile Browser: Safari, iOS 16.1.2