installer: run pip with --no-user

On Windows, when Python is installed from the Microsoft Store, pip is
configured to always run with the --user option.

In any other environment, where the user may have forced the user of
--user, this will also break the installer.

The --no-user option will override any default set in pip.ini.

Fixes python-poetry#4195

install-poetry.py

@@ -516,7 +516,7 @@ def make_env(self, version: str) -> Path:
 
         with temporary_directory() as tmp_dir:
             subprocess.check_call(
-                [sys.executable, "-m", "pip", "install", "virtualenv", "-t", tmp_dir],
+                [sys.executable, "-m", "pip", "install", "virtualenv", "--no-user", "-t", tmp_dir],
                 stdout=subprocess.PIPE,
                 stderr=subprocess.STDOUT,
             )