Fix incorrectly size compute in auto3dseg analyzer (#7374)

Fixes #7222

### Description
remove int convert here.

https://github.com/Project-MONAI/MONAI/blob/8fa6931b14ba9617a595fff1d396ac44cc82e207/monai/auto3dseg/analyzer.py#L259

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [ ] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

---------

Signed-off-by: YunLiu <55491388+KumoLiu@users.noreply.github.com>

monai/auto3dseg/analyzer.py

@@ -256,7 +256,7 @@ def __call__(self, data):
  )
 
  report[ImageStatsKeys.SIZEMM] = [
- int(a * b) for a, b in zip(report[ImageStatsKeys.SHAPE][0], report[ImageStatsKeys.SPACING])
+ a * b for a, b in zip(report[ImageStatsKeys.SHAPE][0], report[ImageStatsKeys.SPACING])
  ]
 
  report[ImageStatsKeys.INTENSITY] = [