Added hover and mouse click support for icons left of status bar

Hovering over icons left of status bar now gives a hover effect
indicating said icons are clickable and when user clicks the bunch,
shade is invoked.

Test: Manual test go/sysui-pkt-manual-testing
Fixes: 297176534
Flag: EXEMPT Bugfix
Change-Id: If58abbe3b86e0a497f6541fbeccc5b6d1a3f2e8b