AnimatedComponent [nfc]: Initialize animatedValue based on visible.

Currently, AnimatedComponent has only one caller, and it always
starts by passing `false` for `visible`. Since it never passes
`true` initially, the new path isn't exercised. But we should make
it so future callers that pass `true` initially will actually see
the element start as visible. So, do that.

See more discussion at
  #4914 (comment).

src/animation/AnimatedComponent.js

@@ -26,7 +26,7 @@ export default function AnimatedComponent(props: Props) {
     style,
   } = props;
 
-  const animatedValue = useRef(new Animated.Value(0));
+  const animatedValue = useRef(new Animated.Value(visible === true ? fullValue : 0));
 
   const animate = useCallback(() => {
     Animated.timing(animatedValue.current, {