Fixed cloth automated tests. (#1400)

Bone transforms buffer is not valid when using Null renderer, which caused the test to fail since it reported an error and ultimately crashing as well. For now it's been worked around by checking the pointer is valid and not printing the error when null renderer is used, a task for the Atom team has been created to fix this properly in the future (ATOM-15807).

Gems/NvCloth/Code/Source/Components/ClothComponentMesh/ClothComponentMesh.cpp

@@ -15,6 +15,7 @@
 #include <AzCore/Math/PackedVector3.h>
 
 #include <AtomLyIntegration/CommonFeatures/Mesh/MeshComponentBus.h>
+#include <Atom/RHI/RHIUtils.h>
 
 #include <NvCloth/IClothSystem.h>
 #include <NvCloth/IFabricCooker.h>
@@ -552,7 +553,7 @@ namespace NvCloth
 
             if (!destVerticesBuffer)
             {
-                AZ_Error("ClothComponentMesh", false,
+                AZ_Error("ClothComponentMesh", AZ::RHI::IsNullRenderer(),
                     "Invalid vertex position buffer obtained from the render mesh to be modified.");
                 continue;
             }