dbr quant: better fix for bug with recursion on dequantize (#70128)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70128
Previous code disabled torch_function when dequantizing arguments
to an unquantizeable function. This PR blocklists the dequantize
method from the dequantize hook instead, so we can remove
the previous hack.
Test Plan:
```
python test/test_quantization.py TestQuantizeDBR
```
Reviewed By: ejguan
Differential Revision: D33194396
Pulled By: vkuzo
fbshipit-source-id: 6175c2da637c1d0c93b3fea0ef8218eaee6a2872
