fix(installer): prioritize user-installed packages over server-libs

Change sys.path.insert(0, ...) to sys.path.append(...) for server
site-packages so user-installed packages in system site-packages
take precedence over bundled server-libs packages.

Previously, server-libs were inserted at the front of sys.path,
causing bundled versions to override user-installed versions
(e.g., streamlit).

Author: mfranczel

installer/module/virtual_environment.py

@@ -96,8 +96,9 @@ def import_package_bundle(
             if condition_env:
                 # Write conditional import that checks environment variable
                 pth_content = (
-                    f"import os, sys; "
-                    f"sys.path.append('{bundle_site_package_path}') "
+                    f"import sys, os, sysconfig; "
+                    f"(sys.path.append('{bundle_site_package_path}'), "
+                    f"sys.path.insert(sys.path.index('{bundle_site_package_path}'), sysconfig.get_path('purelib'))) "
                     f"if os.environ.get('{condition_env}', '').lower() == 'true' else None"
                 )
                 pth_file.write(pth_content + "\n")