Issue Summary

A theme can be assigned to a Portfolio-tier milestone even if that has no relation to any of the linked programs

Steps to Reproduce

• Assume Theme A >> Program A
• Assume Theme B >> Program B

1. Create a Portfolio-tier milestone
2. Link Program B
3. Via PATCH call, link Theme A to this milestone

• Linking Theme A to this milestone in UI is not possible as it requires Program A to be linked in advance

Expected Results

• Linking Theme A to this milestone should not be possible as only Program B is linked
• Linking Theme A should be allowed only if Program A is among the linked program IDs

Actual Results

• Theme A is linked to a milestone that has no linkage to Program A

Workaround

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