Fix module can not import correctly issue (Project-MONAI#8015)

Fixes Project-MONAI#8014


### 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`.
- [x] 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>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 2 people

monai/utils/module.py

@@ -13,7 +13,6 @@
 
 import enum
 import functools
-import importlib.util
 import os
 import pdb
 import re
@@ -209,11 +208,13 @@ def load_submodules(
     ):
         if (is_pkg or load_all) and name not in sys.modules and match(exclude_pattern, name) is None:
             try:
+                mod = import_module(name)
                 mod_spec = importer.find_spec(name)  # type: ignore
                 if mod_spec and mod_spec.loader:
-                    mod = importlib.util.module_from_spec(mod_spec)
-                    mod_spec.loader.exec_module(mod)
+                    loader = mod_spec.loader
+                    loader.exec_module(mod)
                     submodules.append(mod)
+
             except OptionalImportError:
                 pass  # could not import the optional deps., they are ignored
             except ImportError as e: