[quant] Fix implementation for `output_quantized_idxs` in convert (#74140)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74140
Previously we did not successfully remove the dequantize node for `dict`, this PR fixes that, tested with
meta-only tests right now but we should follow up with oss tests (with dict output)
Reviewed By: andrewor14
Differential Revision: D34846005
fbshipit-source-id: 4313ed6adff425d73ad19aabedde1200a98f1915
(cherry picked from commit 682abe9ecbd42c4ac1b41891bbc3b79ad522b78a)