[quant] Support for 4-bit quantized EmbeddingBag module (#45865)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/45865
Test Plan:
python test/test_quantization.py TestPostTrainingStatic.test_quantized_embedding_bag
python test/test_quantization.py TestStaticQuantizedModule.test_embedding_bag_api
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D24120995
fbshipit-source-id: c55fc6b2cfd683d14d2a05be7c04f787fdf8cc79
