git clone subprocess NO LONGER FAILS for SSH when key requires passphrase

[nicheeralal]

This pull request addresses the issue described in #1653.

My solution here is to replace the subprocess.check_output() call with subprocess.run(), which allows the SSH passphrase prompt to be passed through to the user.

The subprocess.run() function is more flexible and can interact with the user when necessary, such as prompting for a passphrase.

In this revised function, subprocess.run is used with the check=False argument to avoid immediate failure. The return code and output are then manually checked and handled. This should allow the passphrase prompt to appear and be entered by the user.

I have tested this locally and passed all unit tests. Note, this change required me to modify some of the test cases. This is my process, which was done in a virtual environment:

1. Made sure I was in the directory where you have cloned your fork of Cookiecutter with the modifications.
2. Installed in Editable Mode: Use the following pip command to install your local Cookiecutter directory in editable mode:
   pip install -e .
3. After running the installation command, I verified that my local version of Cookiecutter is installed by checking the installed packages:
   pip list
4. Tested my change in the Cookiecutter code, with Git configured with an SSH key that has a passphrase.
   cookiecutter git+ssh://git@github.com/audreyr/cookiecutter-pypackage.git
5. This command now utilized my modified Cookiecutter code. It prompts for the SSH passphrase as expected.

Thus the issue/s are addressed.