message: Add tf.TensorScatter ops to Flex delegate
  This change closes
diff: @@ -520,6 +520,11 @@ const std::set<std::string>& GetFlexAllowlist() {
  "TensorArrayWrite",
  "TensorArrayWriteV2",
  "TensorArrayWriteV3",
  + "TensorScatterAdd",
  + "TensorScatterMax",
  + "TensorScatterMin",
  + "TensorScatterSub",
  + "TensorScatterUpdate",
  "Tile",
  "TileGrad",
  "Timestamp",
  