[fenix] For https://github.com/mozilla-mobile/fenix/issues/25808: Update method signature for GestureDetector.SimpleOnGestureListener

app/src/main/java/org/mozilla/fenix/browser/SwipeGestureLayout.kt

@@ -57,18 +57,18 @@ class SwipeGestureLayout @JvmOverloads constructor(
 ) : FrameLayout(context, attrs, defStyleAttr) {
 
     private val gestureListener = object : GestureDetector.SimpleOnGestureListener() {
-        override fun onDown(e: MotionEvent?): Boolean {
+        override fun onDown(e: MotionEvent): Boolean {
             return true
         }
 
         override fun onScroll(
-            e1: MotionEvent?,
+            e1: MotionEvent,
-            e2: MotionEvent?,
+            e2: MotionEvent,
             distanceX: Float,
             distanceY: Float,
         ): Boolean {
-            val start = e1?.let { event -> PointF(event.rawX, event.rawY) } ?: return false
+            val start = e1.let { event -> PointF(event.rawX, event.rawY) }
-            val next = e2?.let { event -> PointF(event.rawX, event.rawY) } ?: return false
+            val next = e2.let { event -> PointF(event.rawX, event.rawY) }
 
             if (activeListener == null && !handledInitialScroll) {
                 activeListener = listeners.firstOrNull { listener ->
@@ -81,8 +81,8 @@ class SwipeGestureLayout @JvmOverloads constructor(
         }
 
         override fun onFling(
-            e1: MotionEvent?,
+            e1: MotionEvent,
-            e2: MotionEvent?,
+            e2: MotionEvent,
             velocityX: Float,
             velocityY: Float,
         ): Boolean {