[quant][pt2e][bc-breaking] Set `fold_quantize` to True in `convert_pt2e` (#119425)
Summary: This is a follow up to https://github.com/pytorch/pytorch/pull/118605 to set `fold_quantize` flag to True in `convert_pt2e`
Test Plan: CI
Differential Revision: D53550237
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119425
Approved by: https://github.com/andrewor14
