Feat: FOUNDRY_ENV set to CI should automatically install with --no-commit

[sambacha]

Component

Forge

Describe the feature you would like

If we are in a detected CI environment, it makes sense not to want to commit install dependencies outside those defined already in the existing .gitmodules file. CI environment typically does not even have the correct git config user/author setup anyway. Plus, it makes sense that we want to keep the work tree clean in testing matrix/scenarios/etc.

Additional context

GitHub runners do not have user/author setup, and its a CI env.

Note

Edit: Since the Runner isn't configured with GIT_AUTHOR or GIT_USER, we must explicitly set these in order to run forge install. Instead, why not just detect CI=true and automatically use --no-commit or alternatively if GIT_AUTHOR env is unset (i.e. GIT_AUTHOR='' it will use --no-commit.)