Fixed NvCloth assets, NvCloth automated test scripts, ModelAsset cloning and UI reverse overrides menu crash (#3851)

- Fixed cloth asset, which stopped working due to Updated skeleton logic: #2957 which changes how fbx graph nodes are collected (affecting its names, which is used by cloth modifier).
- Fixed cloth test suite active call to base's run_test function. It stopped working when its signature was changed here: 182d410#diff-3f5d93b0a76c838893693f19f2eacfe3e67040d445d6463c5c425ef5075cb409
- Renamed nvcloth TestSuite_Active.py to TestSuite_Main.py to be consistent with the other test folders.
- Fixed ModelAsset creator clone function. It was missing to copy the material slots, ultimately causing Material Component to show 0 material slots.
- Fixed crash where the revert overrides menu was not created when checking changes for selected component and selected entities.

Signed-off-by: moraaar moraaar@amazon.com

Gems/Atom/RPI/Code/Source/RPI.Reflect/Model/ModelAssetCreator.cpp

@@ -118,6 +118,12 @@ namespace AZ
                 }
             }
 
+            const ModelMaterialSlotMap &sourceMaterialSlotMap = sourceAsset->GetMaterialSlots();
+            for (const auto& sourceMaterialSlot : sourceMaterialSlotMap)
+            {
+                creator.AddMaterialSlot(sourceMaterialSlot.second);
+            }
+
             return creator.End(clonedResult);
         }
     } // namespace RPI