Add userbase library dir to windows dll search path (#125684)

Fixes #125109 which is a regression introduced by pytorch/builder#1467 that adds dynamic dependency to mkl, which if installed in the user-dir is placed into `sysconfig.sysconfig.get_config_var("userbase") / "Library" / "bin"`

Fix this one, but adding `userbase` folder to the DLL search path

Testing before this fix:
```
Python 3.12.3 (tags/v3.12.3:f6650f9, Apr  9 2024, 14:05:25) [MSC v.1938 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import torch
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\Administrator\AppData\Roaming\Python\Python312\site-packages\torch\__init__.py", line 141, in <module>
    raise err
OSError: [WinError 126] The specified module could not be found. Error loading "C:\Users\Administrator\AppData\Roaming\Python\Python312\site-packages\torch\lib\shm.dll" or one of its dependencies.
>>> exit()
```

After:
```
c:\Program Files\Python312>python
Python 3.12.3 (tags/v3.12.3:f6650f9, Apr  9 2024, 14:05:25) [MSC v.1938 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import torch
>>> exit()
```
Co-authored-by: Nikita Shulga <2453524+malfet@users.noreply.github.com>
Pull Request resolved: #125684
Approved by: https://github.com/malfet

torch/__init__.py

@@ -66,9 +66,11 @@ def _running_with_deploy():
 ################################################################################
 
 if sys.platform == 'win32':
+    import sysconfig
     pfiles_path = os.getenv('ProgramFiles', 'C:\\Program Files')
     py_dll_path = os.path.join(sys.exec_prefix, 'Library', 'bin')
     th_dll_path = os.path.join(os.path.dirname(__file__), 'lib')
+    usebase_path = os.path.join(sysconfig.get_config_var("userbase"), 'Library', 'bin')
 
     # When users create a virtualenv that inherits the base environment,
     # we will need to add the corresponding library directory into
@@ -79,7 +81,7 @@ def _running_with_deploy():
     else:
         base_py_dll_path = ''
 
-    dll_paths = list(filter(os.path.exists, [th_dll_path, py_dll_path, base_py_dll_path]))
+    dll_paths = list(filter(os.path.exists, [th_dll_path, py_dll_path, base_py_dll_path, usebase_path]))
 
     if all(not os.path.exists(os.path.join(p, 'nvToolsExt64_1.dll')) for p in dll_paths):
         nvtoolsext_dll_path = os.path.join(