Useless context for snippet generator in MBPL folder

When accessing a multi-branch pipeline's snippet generator, the context is the multibranch folder, not an individual pipeline job.

This results in the triggers section for prooperties to have the folder's triggers, which are misleading to pipeline creators.

This should show a branch pipeline's applicable triggers instead.

Use case (i.e. "why not just access the branch project?"):
Access to MBPL snippet generator before having Jenkinsfiles. Sort of a chicken/egg problem.