[AddonManager] Fix Error on Existing Python Additional Packages Folder (#14522)

* [AddonManager] Fix Error on Existing Python Additional Packages Folder

...this is more likely to occur since the BIM workbench integration and new users installing ifcOpenShell by pip before running AddonManager.

* [AddonManager] Correct boolean

src/Mod/AddonManager/manage_python_dependencies.py

@@ -389,8 +389,7 @@ class PythonPackageManager:
             # Nothing to migrate
             return False
 
-        if not os.path.exists(new_directory):
-            os.makedirs(new_directory)
+        os.makedirs(new_directory, mode=0o777, exist_ok=True)
 
         for content_item in os.listdir(old_directory):
             if content_item == new_directory_name: