Sets defaults for optional inputs so they always have values

[lorengordon]

No description provided.

[lorengordon]

results of make test:

> make terraform/pytest PYTEST_ARGS="-v --nomock"
[bootstrap]: Using external tardigrade-ci, skipping auto-init
[pytest//home/x/git/repos/tardigrade-ci/tests/terraform_pytest] Starting Python tests found under the directory "/home/x/git/repos/tardigrade-ci/tests/terraform_pytest"
pytest /home/x/git/repos/tardigrade-ci/tests/terraform_pytest -v --nomock
==================================================== test session starts =====================================================
platform linux -- Python 3.10.13, pytest-7.4.3, pluggy-1.3.0 -- /home/x/.pyenv/versions/3.10.13/bin/python3.10
cachedir: .pytest_cache
rootdir: /home/x/git/repos
collected 1 item

../tardigrade-ci/tests/terraform_pytest/test_terraform_install.py::test_modules[create_all] PASSED                                                                                                                                                                                           [100%]

===================================================== 1 passed in 31.42s =====================================================
[pytest//home/x/git/repos/tardigrade-ci/tests/terraform_pytest]: Tests executed!