Modify APoT dequantize method (#82126)
### Summary
Modify APoT dequantize method to correctly add dequantized values to result numpy array and retain original tensor dimensions
### Test Plan
Run unit tests with: `python test/quantization/core/experimental/test_quantizer.py`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82126
Approved by: https://github.com/HDCharles
