Selection is not restored in project tree after closing and opening parent folder

[jasonsanjose]

1. Select a file nested at least 1 level deep in the project file tree
2. Close and reopen the parent folder

Observe that even though the file is still open in an editor, it doesn't appear as selected in the tree. This bug reproduces in sprint 6 as well and is not a regression from the northstar UI implementation.

It appears that jstree isn't maintaining a selected state for descendant nodes when an ancestor is closed and reopened.

[njx]

QRB reviewed. Bumping to medium priority and tagging for sprint 8.