Preserve the exit-code for "fail-fast: false" mode

The fail-fast mode will exit with non-zero code _immediately_ when there's an error in deployment. This is as intended.

However, currently, when the fail-fast mode is disabled and there's an error in deployment, BitOps will run until the end and exit with `0` return code like it was a success.

The expectation from the fail-fast: false mode is to run all the deployment steps, but defer the error code (if any) and bubble it up to the BitOps finish exit code. This way we exit with non-zero if some deployment in the middle of the pipeline was unsuccessful.

No files, tests, or entry points are named in the issue. Start by searching the deployment pipeline for the fail-fast setting and its final exit-status handling; done means all steps still run when fail-fast is false, while any deployment error produces a non-zero BitOps exit code.

Written by the indexing model from the issue text.