fix(safari): Update the check for Safari

In preparation for the lib-jitsi-meet PR for Safari support, isSafariWithWebrtc() will no longer be available

modules/UI/videolayout/VideoContainer.js

         // explicitly disabled.
         if (interfaceConfig.DISABLE_VIDEO_BACKGROUND
                 || browser.isFirefox()
-                || browser.isSafariWithWebrtc()) {
+                || browser.isSafari()) {
             return;
         }