fix: throw an error on deployment errors triggered via the api

[shreddedbacon]

General Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for inclusion in changelog

Database Migrations

• If your PR contains a database migation, it MUST be the latest in date order alphabetically

Closing issues

• [deploy branch command] Exit code returns 0, should return > 0 for errors  lagoon-cli#189

[shreddedbacon]

This is just a place holder, probably not to be merged because unsure how far this possibly breaks

[tobybellwood]

As odd as the logic may seem, we should flag this as a deprecation to change in a future release.

"We will be deprecating the returning of these as error strings, in favour of returning an actual error"

[tobybellwood]

Happy to move forwards with these. Will post a clear message in the release notes that errors are now actually errors. Will go through all internal tools to ensure they work as expected