Demote error to warning for tier 3 descriptor exhaustion

* This is sadly common enough that we will hit it regularly on many D3D12
  programs that just allocate the maximum number of descriptors.

renderdoc/driver/d3d12/d3d12_device_wrap.cpp

@@ -959,7 +959,7 @@ bool WrappedID3D12Device::Serialise_CreateDescriptorHeap(
 
     if(patched && FAILED(hr))
     {
-      RDCERR(
+      RDCWARN(
           "RenderDoc needs extra descriptors for patching during analysis,"
           "but heap failed to expand any further even at tier 3");
       PatchedDesc.NumDescriptors = Descriptor.NumDescriptors;