[JENKINS-63197] Use cli properties only if they are defined

[PierreBtz]

Opening as a draft as I'd like to cover this part with additional tests.

I'm also unsure if the API is considered as stable in this project? In the current state of this PR I'm happily breaking it :)

[PierreBtz]

After playing around a bit more I'm under the impression I initially missed something in that I should probably not invest any time in playing with BOM (JEP-309) as the format has been more or less dropped with the plugin installer using a different format and being the future of plugin management outside of a running Jenkins. Am I missing something?

[oleg-nenashev]

After playing around a bit more I'm under the impression I initially missed something in that I should probably not invest any time in playing with BOM (JEP-309) as the format has been more or less dropped with the plugin installer using a different format and being the future of plugin management outside of a running Jenkins. Am I missing something?

You don't miss anything. After Jenkins Evergreen was abandoned, there is no real usages of the Jenkins BOM YAMLs in the production codebase. Personally I mostly switched to pom.xml inputs

[PierreBtz]

Closing the PR for now, as the BOM future is not clear I won't be using it for now, so I won't finish fixing up the various issues with it in the CLI.