Merge branch 'getsoundplaying' into 'master'

Don't require a reference for GetSoundPlaying (#8389)

Closes #8389

See merge request OpenMW/openmw!4576

Author: psi29a

apps/openmw/mwscript/soundextensions.cpp

@@ -162,11 +162,17 @@ namespace MWScript
         public:
             void execute(Interpreter::Runtime& runtime) override
             {
-                MWWorld::Ptr ptr = R()(runtime);
+                MWWorld::Ptr ptr = R()(runtime, false);
 
                 int index = runtime[0].mInteger;
                 runtime.pop();
 
+                if (ptr.isEmpty())
+                {
+                    runtime.push(0);
+                    return;
+                }
+
                 bool ret = MWBase::Environment::get().getSoundManager()->getSoundPlaying(
                     ptr, ESM::RefId::stringRefId(runtime.getStringLiteral(index)));