Reduce refresh indicator pull-down distance and update related tests (#69783)

Co-authored-by: altherat <contact@altherat.com>

packages/flutter/lib/src/material/refresh_indicator.dart

@@ -258,7 +258,7 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
       }
     } else if (notification is OverscrollNotification) {
       if (_mode == _RefreshIndicatorMode.drag || _mode == _RefreshIndicatorMode.armed) {
-        _dragOffset = _dragOffset! - notification.overscroll / 2.0;
+        _dragOffset = _dragOffset! - notification.overscroll;
         _checkDragOffset(notification.metrics.viewportDimension);
       }
     } else if (notification is ScrollEndNotification) {

packages/flutter/test/material/refresh_indicator_test.dart

@@ -225,7 +225,7 @@ void main() {
       ),
     );
 
-    await tester.fling(find.text('X'), const Offset(0.0, 100.0), 1000.0);
+    await tester.fling(find.text('X'), const Offset(0.0, 50.0), 1000.0);
     await tester.pump();
     await tester.pump(const Duration(seconds: 1));
     await tester.pump(const Duration(seconds: 1));
@@ -233,6 +233,33 @@ void main() {
     expect(refreshCalled, false);
   });
 
+  testWidgets('RefreshIndicator - just enough', (WidgetTester tester) async {
+    refreshCalled = false;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: RefreshIndicator(
+          onRefresh: refresh,
+          child: ListView(
+            physics: const AlwaysScrollableScrollPhysics(),
+            children: const <Widget>[
+              SizedBox(
+                height: 200.0,
+                child: Text('X'),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    await tester.fling(find.text('X'), const Offset(0.0, 100.0), 1000.0);
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 1));
+    await tester.pump(const Duration(seconds: 1));
+    await tester.pump(const Duration(seconds: 1));
+    expect(refreshCalled, true);
+  });
+
   testWidgets('RefreshIndicator - show - slow', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(