Fix typo in scroll_activity.dart (#79771)

AUTHORS

@@ -75,3 +75,4 @@ vimerzhao <vimerzhao@gmail.com>
 Pedro Massango <pedromassango.developer@gmail.com>
 Hidenori Matsubayashi <Hidenori.Matsubayashi@sony.com>
 Perqin Xie <perqinxie@gmail.com>
+Seongyun Kim <helloworld@cau.ac.kr>

packages/flutter/lib/src/widgets/scroll_activity.dart

@@ -278,7 +278,7 @@ class ScrollDragController implements Drag {
   /// the end of a drag. Expressed as a factor. For example with a
   /// [carriedVelocity] of 2000, we will need a velocity of at least 1000 to
   /// apply the [carriedVelocity] as well. If the velocity does not meet the
-  /// threshold the the [carriedVelocity] is lost. Decided by fair eyeballing
+  /// threshold, the [carriedVelocity] is lost. Decided by fair eyeballing
   /// with the scroll_overlay platform test.
   static const double momentumRetainVelocityThresholdFactor = 0.5;