[Unity] Fix ConvertLayout on binary elemwise ops involving scalar input

[masahi]

Currently when one of the inputs to elemwise op is a scalar, ConvertLayout inserts NHWC -> NCHW fallback conversion, ending up the following undesirable result:

gv: R.Tensor((2, 26, 26, 4), dtype="float32") = R.nn.conv2d(lv, lv1, data_layout="NHWC", kernel_layout="OHWI", out_layout="NHWC")
lv2: R.Tensor((2, 4, 26, 26), dtype="float32") = R.permute_dims(gv, axes=[0, 3, 1, 2])
gv2: R.Tensor((2, 4, 26, 26), dtype="float32") = R.add(lv2, R.const(1, "float32"))

@spectrometerHBH

[tvm-bot]

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• cc @quic-sanirudh _{See #10317 for details}

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[masahi]

ping @spectrometerHBH