chore: update docs to use the new large anchored adaptive banner

Author: dylancom

RNGoogleMobileAdsExample/App.tsx

@@ -270,7 +270,7 @@ class CollapsibleBannerTest implements AutoExecutableTest {
       <View ref={onMount}>
         <BannerAd
           unitId={TestIds.ADAPTIVE_BANNER}
-          size={BannerAdSize.ANCHORED_ADAPTIVE_BANNER}
+          size={BannerAdSize.LARGE_ANCHORED_ADAPTIVE_BANNER}
           requestOptions={{
             networkExtras: {
               collapsible: 'top',

docs/displaying-ads.mdx

@@ -432,7 +432,7 @@ function App() {
   });
 
   return (
-    <BannerAd ref={bannerRef} unitId={adUnitId} size={BannerAdSize.ANCHORED_ADAPTIVE_BANNER} />
+    <BannerAd ref={bannerRef} unitId={adUnitId} size={BannerAdSize.LARGE_ANCHORED_ADAPTIVE_BANNER} />
   );
 }
 ```
@@ -479,7 +479,7 @@ function App() {
   return (
     <BannerAd
       unitId={adUnitId}
-      size={BannerAdSize.ANCHORED_ADAPTIVE_BANNER}
+      size={BannerAdSize.LARGE_ANCHORED_ADAPTIVE_BANNER}
       requestOptions={{
         networkExtras: {
           collapsible: 'bottom',