Dependencies for sub-task throws misleading cyclic dependency error

Summary

It is known that Portfolio for Jira doesn't support dependency for sub-tasks. However, the error thrown is causing confusion within the plan to detect the offending dependencies. With the error cyclic dependency is thrown, users will start to look for a cyclic dependency without knowing that a dependency set for sub-task is the cause.

Suggested fix

A specific error relevant to the cause should be thrown.