Escape should consistently close flyouts

[gonfunko]

Currently, pressing Escape when a flyout is focused will close it only if it is an autoclosing flyout. Escape should also close non-autoclosable flyouts, as long as they are not a simple toolbox, including e.g. the trash and backpack flyouts.

[maribethb]

we need to make sure that however we implement this doesn't close flyouts that are never closed normally, such as the continuous toolbox. i'm not sure that we currently have a good api to detect this kind of toolbox, because it relies on the toolbox being subclassed to not close the flyout when you click an open category.