Replace hasattr with getattr in pytorch/opacus/opacus/data_loader.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.**

Differential Revision: D44886833

fbshipit-source-id: 1e5b91a1aaace39425468b0c777fb03e59a6ec28

Author: r-barnes

opacus/data_loader.py

@@ -70,7 +70,7 @@ def shape_safe(x: Any) -> Tuple:
     Returns:
         ``x.shape`` if attribute exists, empty tuple otherwise
     """
-    return x.shape if hasattr(x, "shape") else ()
+    return getattr(x, "shape", ())
 
 
 def dtype_safe(x: Any) -> Union[torch.dtype, Type]:
@@ -83,7 +83,7 @@ def dtype_safe(x: Any) -> Union[torch.dtype, Type]:
     Returns:
         ``x.dtype`` if attribute exists, type of x otherwise
     """
-    return x.dtype if hasattr(x, "dtype") else type(x)
+    return getattr(x, "dtype", type(x))
 
 
 class DPDataLoader(DataLoader):