Plan branch key can't be used for trigger condition

Issue Summary

Trigger condition "Only run Build if other Plans are currently passing" doesn't allow to use plan branch key 

Steps to Reproduce

1. Create plan A with key PRJ-PLANA.
2. Create plan branch which has a key PRJ-PLANA0
3. Create plan B with trigger 
4. Add condition "Only run Build if other Plans are currently passing" and provide key PRJ-PLANA0
5. Save trigger configuration

Expected Results

Configuration is saved and used for trigger condition.

Actual Results

Validation error

PLANBRANCH-KEY is a job and can not be used in this field.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available