Improve GetModuleFileName tests and clarify virtual environment behavior.

[junkmd]

A test for GetModuleFileName with a null handler was failing in virtual environments (like with uvx).

PS C:\path\to\prj\comtypes> uvx python -m unittest comtypes.test.test_typeinfo.Test_GetModuleFileName                  
test_invalid_handle (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_invalid_handle) ... ok                              
test_invalid_nsize (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_invalid_nsize) ... ok
test_loaded_module_handle (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_loaded_module_handle) ... ok
test_null_handler (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_null_handler) ... FAIL

======================================================================
FAIL: test_null_handler (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_null_handler)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\path\to\prj\comtypes\comtypes\test\test_typeinfo.py", line 100, in test_null_handler
    self.assertEqual(GetModuleFileName(None, MAX_PATH), sys.executable)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'C:\\[18 chars]ata\\Roaming\\uv\\python\\cpython-3.13.9-windo[22 chars].exe' != 'C:\\[18 chars]ata\\Local\\uv\\cache\\archive-v0\\fYwvsebcHXF[27 chars].exe'
- C:\path\to\prj\AppData\Roaming\uv\python\cpython-3.13.9-windows-x86_64-none\python.exe
+ C:\path\to\prj\AppData\Local\uv\cache\archive-v0\fYwvsebcHXFVIUUYHU9HQ\Scripts\python.exe


----------------------------------------------------------------------
Ran 4 tests in 0.001s

FAILED (failures=1)

The test expecting sys.executable is now skipped in virtual environments.
A new test was added to verify the path returned is under sys.base_prefix.

PS C:\path\to\prj\comtypes> uvx python -m unittest comtypes.test.test_typeinfo.Test_GetModuleFileName -v
test_invalid_handle (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_invalid_handle) ... ok                              
test_invalid_nsize (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_invalid_nsize) ... ok
test_loaded_module_handle (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_loaded_module_handle) ... ok
test_null_handler_sys_base_prefix (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_null_handler_sys_base_prefix) ... ok  
test_null_handler_sys_executable (comtypes.test.test_typeinfo.Test_GetModuleFileName.test_null_handler_sys_executable) ... skipped 'This will fail in a virtual environment.'

----------------------------------------------------------------------
Ran 5 tests in 0.001s

OK (skipped=1)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.70%. Comparing base (fb8fd58) to head (ed2f9e7).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #875   +/-   ##
=======================================
  Coverage   84.69%   84.70%           
=======================================
  Files         125      125           
  Lines       11532    11536    +4     
=======================================
+ Hits         9767     9771    +4     
  Misses       1765     1765           

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