fx quant: remove `find_quants` from convert (#57402)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57402
This is a cleanup, the value is not used by anything. It was
probably left behind after previous refactors.
Test Plan:
```
python test/test_quantization.py TestQuantizeFx
python test/test_quantization.py TestQuantizeFxOps
```
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D28133622
fbshipit-source-id: 44a3f955d4af8d6dd15b4fb3038188568e4ee549
