Fixed casting logic for hashing to be based on raw type in order to support key types correctly

Author: harishsk

src/Microsoft.ML.Data/Transforms/Hashing.cs

@@ -1359,7 +1359,7 @@ private bool SaveAsOnnxCore(OnnxContext ctx, int iinfo, string srcVariable, stri
                 OnnxNode murmurNode;
                 OnnxNode isZeroNode;
 
-                var srcType = _srcTypes[iinfo].GetItemType();
+                var srcType = _srcTypes[iinfo].GetItemType().RawType;
                 if (_parent._columns[iinfo].Combine)
                     return false;
 
@@ -1386,9 +1386,9 @@ private bool SaveAsOnnxCore(OnnxContext ctx, int iinfo, string srcVariable, stri
                 }
 
                 // Since these numeric types are not supported by Onnxruntime, we cast them to UInt32.
-                if (srcType == NumberDataViewType.UInt16 || srcType == NumberDataViewType.Int16 ||
-                    srcType == NumberDataViewType.SByte || srcType == NumberDataViewType.Byte ||
-                    srcType == BooleanDataViewType.Instance || srcType is KeyDataViewType)
+                if (srcType == typeof(ushort) || srcType == typeof(short) ||
+                    srcType == typeof(sbyte) || srcType == typeof(byte) ||
+                    srcType == typeof(bool))
                 {
                     castOutput = ctx.AddIntermediateVariable(NumberDataViewType.UInt32, "CastOutput", true);
                     castNode = ctx.CreateNode("Cast", srcVariable, castOutput, ctx.GetNodeName(opType), "");