title: Unable to close AdMob interstitial ad
body: <p>Lately, my android app has been showing Admob interstitial ads that cannot be dismissed.  It seems the back button action to dismiss an ad was discontinued.  Most interstitial ads include a "Close" button on the ad itself, but not all of them do.  When an interstitial ad is delivered without a close button, the only way to close the ad is to kill the app.</p>
  
  <p>Here is an example of an ad we received without a close button:</p>
  
  <p><a href="https://i.stack.imgur.com/wpL3l.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/wpL3l.jpg" alt="enter image description here"></a>  </p>
  
  <p>I am using 
  <code>implementation 'com.google.android.gms:play-services-ads:17.0.0'</code></p>
  
  <p>in my Gradle build.</p>
  
  <p>So the question is:  Is there any way to close an interstitial ad aside from pressing the close button on the ad?  </p>