[BottomSheetBehavior] Ignore ACTION_MOVE events in BottomSheetBehavio…

…r that weren't preceded by an ACTION_DOWN event.

PiperOrigin-RevId: 512670230

lib/java/com/google/android/material/bottomsheet/BottomSheetBehavior.java

@@ -215,6 +215,8 @@ void onLayout(@NonNull View bottomSheet) {}
 
   private static final int VIEW_INDEX_BOTTOM_SHEET = 0;
 
+  private static final int INVALID_POSITION = -1;
+
   @VisibleForTesting
   static final int VIEW_INDEX_ACCESSIBILITY_DELEGATE_VIEW = 1;
 
@@ -319,7 +321,7 @@ void onLayout(@NonNull View bottomSheet) {}
 
   int activePointerId;
 
-  private int initialY;
+  private int initialY = INVALID_POSITION;
 
   boolean touchingScrollingChild;
 
@@ -653,6 +655,7 @@ public boolean onInterceptTouchEvent(
         && state != STATE_DRAGGING
         && !parent.isPointInChildBounds(scroll, (int) event.getX(), (int) event.getY())
         && viewDragHelper != null
+        && initialY != INVALID_POSITION
         && Math.abs(initialY - event.getY()) > viewDragHelper.getTouchSlop();
   }
 
@@ -1460,6 +1463,7 @@ private float calculateSlideOffsetWithTop(int top) {
 
   private void reset() {
     activePointerId = ViewDragHelper.INVALID_POINTER;
+    initialY = INVALID_POSITION;
     if (velocityTracker != null) {
       velocityTracker.recycle();
       velocityTracker = null;