Toolbar: Allow layout changes to be animated

[pocmo]

We can show/hide/update actions dynamically now. To make this smooth we should allow those changes to be animated.

My hope here is to use animateLayoutChanges of ViewGroup:
https://developer.android.com/reference/android/view/ViewGroup.html#attr_android:animateLayoutChanges

┆Issue is synchronized with this Jira Task

[pocmo]

animateLayoutChanges works nicely! ❤️