Assert availability of libwebrtc

https://bugs.webkit.org/show_bug.cgi?id=274991
rdar://problem/129080708

Reviewed by Alexey Proskuryakov and Brent Fulgham.

If for some reason libwebrtc is not present, we could crash assert immediately instead of crash on a bad access.
Also, we are reverting https://commits.webkit.org/279586@main where we would not crash if libwebrtc
would not be available.

* Source/WebCore/platform/mediastream/libwebrtc/LibWebRTCProviderCocoa.cpp:
(WebCore::WebRTCProvider::webRTCAvailable):

Canonical link: https://commits.webkit.org/279610@main

Source/WebCore/platform/mediastream/libwebrtc/LibWebRTCProviderCocoa.cpp

@@ -102,7 +102,8 @@ void LibWebRTCProviderCocoa::setActive(bool value)
 
 bool WebRTCProvider::webRTCAvailable()
 {
-#if (PLATFORM(IOS) || PLATFORM(VISION)) && !PLATFORM(IOS_SIMULATOR)
+#if PLATFORM(IOS) || PLATFORM(VISION)
+    ASSERT_WITH_MESSAGE(!!webrtc::setApplicationStatus, "Failed to find or load libwebrtc");
     return true;
 #else
     return !!webrtc::setApplicationStatus;