Account for momentum when hiding minimal shell (#3740)

* Add optional momentum events to scroll context

* If there is a velocity, don't snap until momentum end

* Don't show bar on scroll down

* Rm onMomentumBegin

src/view/com/util/List.tsx

@@ -64,6 +64,11 @@ function ListImpl<ItemT>(
         }
       }
     },
+    // Note: adding onMomentumBegin here makes simulator scroll
+    // lag on Android. So either don't add it, or figure out why.
+    onMomentumEnd(e, ctx) {
+      contextScrollHandlers.onMomentumEnd?.(e, ctx)
+    },
   })
 
   let refreshControl