Merge pull request #98305 from cadence-s/fix-ios-audio-driver-error

Fix iOS audio driver attempting to start output too early

drivers/coreaudio/audio_driver_coreaudio.cpp

@@ -250,7 +250,7 @@ OSStatus AudioDriverCoreAudio::input_callback(void *inRefCon,
 }
 
 void AudioDriverCoreAudio::start() {
-	if (!active) {
+	if (!active && audio_unit != nullptr) {
 		OSStatus result = AudioOutputUnitStart(audio_unit);
 		if (result != noErr) {
 			ERR_PRINT("AudioOutputUnitStart failed, code: " + itos(result));