Force expand active node in TreeBuilder

[skateman]

The BZ below is a little bit complicated, a minimal reproducer is to navigate to Settings -> Access Control -> Users with a clean session and add a new user or edit an existing user's name. The changes will be affected on the right side, but not on the left.

The problem is that the expanded state of a lazily-loaded node isn't reflected until a full page reload. However, by navigating to the Users node the active node parameter is being set properly and this can be leveraged when setting the expanded state of the node itself.

@miq-bot add_reviewer @ZitaNemeckova
@miq-bot add_label gaprindashvili/yes, bug, trees

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1561698

[miq-bot]

Checked commit skateman@631afc7 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 0 offenses detected
Everything looks fine. 🏆

[ZitaNemeckova]

Configuration -> Access Control -> Users is not expanded -> click Users -> Configuration -> Add/Edit a User

Add new user
Before:

No Pepik user in left tree
After:

Namornik user in left tree

Edit a user
Before:

Pepek neni Namornik is not changed to Pepek Namornik in left tree
After:

Pepek neni Namornik is changed to Pepek neni Namornik in left tree

So LGTM 👍

[ZitaNemeckova]

LGTM 👍