Prevent side nav auto-collapse

[catherineluse]

This PR fixes #6658 and partly addresses #4431 (comment)

Changes in this PR:

• Side nav in Cluster Explorer no longer auto-collapses as you navigate
• You can now have more than one group expanded in the side nav

Reasons for the change:

• We got customer feedback that the auto-collapse is disconcerting (Rethink how we show nav links and keep top-level groups in menu all the time #4431 (comment))
• There is an accessibility guideline that says we should avoid rearranging content in a way that users would not expect

Screenshot of multiple groups expanded:

To test this PR, I went to Cluster Explorer and:

• Confirmed that when a nav group is clicked, it expands
• When an expanded group is clicked, it collapses
• When collapsing a group that is actively selected, it is still marked as active/highlighted
• Changing between different nav items does not auto-collapse nav items

Note: I think the auto-collapse may have originally been intended to prevent an issue with the nav becoming too long for the page, but we no longer have this problem due to the scroll bar on the nav section

[nwmac]

@catherineluse The auto-collapse was added because the feedback from users was that the navigation was overwhelming. I think we need to discuss this change with @kwwii

[richard-cox]

I think when we didn't auto-collapse menu groups there was some weirdness when the resource was starred, think both starred and the menu group would open up. Worth testing for regressions.

[catherineluse]

Related to SURE-3658