[quant][pt2e][be] Move annotate helper function to quantizer/utils.py (#102127)
Summary: att
Test Plan:
```
buck2 test mode/opt caffe2/test:quantization_pt2e -- --exact 'caffe2/test:quantization_pt2e - test_resnet18_with_quantizer_api (quantization.pt2e.test_quantize_pt2e.TestQuantizePT2EModels)'
```
Reviewed By: kimishpatel
Differential Revision: D46001285
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102127
Approved by: https://github.com/kimishpatel
