Fix addAllowedPointer() overrides (#82834)

They should have been taking a PointerDownEvent.

This change was originally included in #81884, but that
had to be reverted because it broke Google testss. This
sub-part of that larger change needs to be made first in
order to allow for a phased rollout in a way that won't
break Google tests.

https://github.com/flutter/flutter/issues/81883

packages/flutter/lib/src/gestures/force_press.dart

@@ -216,7 +216,7 @@ class ForcePressGestureRecognizer extends OneSequenceGestureRecognizer {
   _ForceState _state = _ForceState.ready;
 
   @override
-  void addAllowedPointer(PointerEvent event) {
+  void addAllowedPointer(PointerDownEvent event) {
     // If the device has a maximum pressure of less than or equal to 1, it
     // doesn't have touch pressure sensing capabilities. Do not participate
     // in the gesture arena.

packages/flutter/lib/src/gestures/monodrag.dart

@@ -262,7 +262,7 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
   }
 
   @override
-  void addAllowedPointer(PointerEvent event) {
+  void addAllowedPointer(PointerDownEvent event) {
     startTrackingPointer(event.pointer, event.transform);
     _velocityTrackers[event.pointer] = velocityTrackerBuilder(event);
     if (_state == _DragState.ready) {

packages/flutter/lib/src/gestures/multitap.dart

@@ -507,7 +507,7 @@ class MultiTapGestureRecognizer extends GestureRecognizer {
   final Map<int, _TapGesture> _gestureMap = <int, _TapGesture>{};
 
   @override
-  void addAllowedPointer(PointerEvent event) {
+  void addAllowedPointer(PointerDownEvent event) {
     assert(!_gestureMap.containsKey(event.pointer));
     _gestureMap[event.pointer] = _TapGesture(
       gestureRecognizer: this,

packages/flutter/lib/src/gestures/scale.dart

@@ -350,7 +350,7 @@ class ScaleGestureRecognizer extends OneSequenceGestureRecognizer {
   }
 
   @override
-  void addAllowedPointer(PointerEvent event) {
+  void addAllowedPointer(PointerDownEvent event) {
     startTrackingPointer(event.pointer, event.transform);
     _velocityTrackers[event.pointer] = VelocityTracker.withKind(event.kind);
     if (_state == _ScaleState.ready) {