[AppBarLayout] Allow scrolling up when the app bar is lifted.

1. Suppose the view is large enough to scroll down
2. After scrolling down, you hide a child view, which reduces the height to a value which means it would have been unscrollable in step 1
3. Now you can’t scroll back up

PiperOrigin-RevId: 623883120

Author: Material Design Team

lib/java/com/google/android/material/appbar/AppBarLayout.java

@@ -1533,7 +1533,9 @@ public boolean onStartNestedScroll(
       // or we can scroll the children.
       final boolean started =
           (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0
-              && (child.isLiftOnScroll() || canScrollChildren(parent, child, directTargetChild));
+              && (child.isLiftOnScroll()
+                  || child.isLifted()
+                  || canScrollChildren(parent, child, directTargetChild));
 
       if (started && offsetAnimator != null) {
         // Cancel any offset animation