Replace hasattr with getattr in pytorch/benchmark/torchbenchmark/models/torchrec_dlrm/data/dlrm_dataloader.py
Summary:
The pattern
```
X.Y if hasattr(X, "Y") else Z
```
can be replaced with
```
getattr(X, "Y", Z)
```
The [getattr](https://www.w3schools.com/python/ref_func_getattr.asp) function gives more succinct code than the [hasattr](https://www.w3schools.com/python/ref_func_hasattr.asp) function. Please use it when appropriate.
**This diff is very low risk. Green tests indicate that you can safely Accept & Ship.**
Reviewed By: xuzhao9
Differential Revision: D44886824
fbshipit-source-id: 2a85aafb487e81f72e999d284889406f9ff5a16b