Design explorer forgets collapse state

[Stevenic]

Describe the bug

You can collapse the rigger list for various dialogs and the explorer generally remembers this collapse state as you browse around the project. The moment you try to view the settings for a given dialog, however, all of the collapse states are forgotten.

Version

https://github.com/microsoft/BotFramework-Composer-Nightlies/releases/tag/v1.1.1-nightly.178300.83c0804