Catch exceptions when we can't play audio

...or try to: the chrome debugger still breakpoints, even when we
catch the exception.

Related to, but probably does not fix https://github.com/vector-im/riot-web/issues/7657

src/Notifier.js

@@ -146,7 +146,7 @@ const Notifier = {
                 }
                 document.body.appendChild(audioElement);
             }
-            audioElement.play();
+            await audioElement.play();
         } catch (ex) {
             console.warn("Caught error when trying to fetch room notification sound:", ex);
         }