Return the deployment result in exit code for all failures

[demolitionmode]

Which issue(s) does this change fix?

#5103

Why is this change necessary?

When a stack fails to deploy, the exit code should reflect this regardless of it being rolled back (through use of --on-failure DELETE)

How does it address the issue?

Setting --on-failure DELETE no longer skips the raise line; rather, the condition will only determine whether deployer.rollback_delete_stack() is called or not.

What side effects does this change have?

Users who rely on the previous behaviour would need to ignore this fix, with something like sam deploy || true

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[mildaniel]

Thanks @demolitionmode for raising this PR. As you mentioned, this is technically a breaking change that can impact existing customer. We might need a different way to enable this behaviour that is opt-in instead of by default, potentially a new command line flag.

I will bring this to the team to discuss the best approach.

[mildaniel]

After discussing with the team, we think it's okay to proceed with this PR. When ready, we will create an announcement explain this change in behaviour to existing customers.