Updated MuteThisAd sample to use alloc instead of new.

PiperOrigin-RevId: 642138309

Author: nventimigli

Objective-C/advanced/APIDemo/APIDemo/AdMobNativeCustomMuteThisAdViewController.m

@@ -62,7 +62,7 @@ - (IBAction)refreshAd:(id)sender {
   self.refreshButton.enabled = NO;
 
   // Provide the custom mute this ad loader options to request custom mute feature.
-  GADNativeMuteThisAdLoaderOptions *muteOptions = [GADNativeMuteThisAdLoaderOptions new];
+  GADNativeMuteThisAdLoaderOptions *muteOptions = [[GADNativeMuteThisAdLoaderOptions alloc] init];
   self.adLoader = [[GADAdLoader alloc] initWithAdUnitID:GADAPIDemoNativeTestAdUnit
                                      rootViewController:self
                                                 adTypes:@[ GADAdLoaderAdTypeNative ]