Fix navigating scroll to the top of the screen when re-selecting the current tab.

[JorgeMucientes]

Nothing happens when re-selecting the current tab. It should scroll to the top of the screen when doing this.
One thing I noticed is scrollToTop() function from TopLeverFragment is never called when re-selecting the tab. This happens to all the other tabs as well and it is because getActiveTopLevelFragment() returns null always, when reselecting any tab. I don't know since when this is broken and haven't had the time to dig deper

Additionally review shouldExpandToolbar() for DashboardFragment to ensure the collapsing toolbar is shown collapsed when navigating back to My Store and the scroll position is not at the top.

[dangermattic]

🚫 Please add a type label (e.g. type: enhancement) and a feature label (e.g. feature: stats) to this issue.