iOS 13 Full Screen: Dragging items down exits full screen

[KatieWoe]

For phetsims/qa#427.
Dragging the sim down with one finger causes iOS to exit full screen. However, if you are dragging an object down this activates even when you have clearly grabbed and are dragging the object in question. Only seems to happen if you start by dragging down. Good example is dragging the litmus paper into the solution in acid-base-solution
@ariel-phet for priority/strategy

[jonathanolson]

This is also present in 13.0, and I don't have a good way to handle this other than preventing full-screen.

[ariel-phet]

In #64 we decided we should investigate detection of iOS 13 and attempt to disable full-screen in those cases. Referencing that issue here, and assigning @jonathanolson to include this issue as part of QA testing for the maintenance release. If disabling full-screen works, then this issue should be moot and will be able to be closed.