Adds support to tgw and vpc attachments for security group referencing

[lorengordon]

No description provided.

[yiltis-p3]

LGTM, approved!

[lorengordon]

Results of make test:

❯ !20041
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 3.8.18, pytest-8.2.2, pluggy-1.5.0 -- /home/x/.pyenv/versions/3.8.18/bin/python3.8
cachedir: .pytest_cache
rootdir: /home/x/git/repos
collected 4 items

../tardigrade-ci/tests/terraform_pytest/test_terraform_install.py::test_modules[cross-account-vpc-attachment] PASSED                                                                                                  [ 25%]
../tardigrade-ci/tests/terraform_pytest/test_terraform_install.py::test_modules[cross-region-peering-attachment] PASSED                                                                                               [ 50%]
../tardigrade-ci/tests/terraform_pytest/test_terraform_install.py::test_modules[cross-account-vpc-attachment-auto-acceptor] PASSED                                                                                    [ 75%]
../tardigrade-ci/tests/terraform_pytest/test_terraform_install.py::test_modules[tgw] PASSED                                                                                                                           [100%]

=========== 4 passed in 2042.80s (0:34:02) ============
[pytest//home/x/git/repos/tardigrade-ci/tests/terraform_pytest]: Tests executed!