This reverts commit 740ae2d1, reversing
changes made to 1ba47de5.

This reverts commit 2411ecb5, reversing
changes made to 58a0df7e.

Discussions were being toggled by jquery DOM querying them and toggling
visibility but in vue, only the open discussions will be in the DOM
Fix includes:
 - Adds a getter to the store to get the expanded discussions
 - Adds an action to collapse a discussion
 - When the user clicks the button, all data needed is now accessible
   through a getter and we can dispatch an action to toggle the discussion
   within the state, instead of showing/hiding with jQuery
 - Removes hardcoded properties

Resolves #48237

Exports state to allow tests
Adds specs for the getters that didn't have any.