[Spike] Investigate efficient logic for scan result policy with parent-child pipelines

Description

While working on Compare results from all pipelines related to c... (#379108 - closed) we found that parent-child pipelines would not work with the solution proposed for multiple pipelines feature. Since, Downstream Pipelines can be architected in multiple different ways, having a single solution for all types of possibilities is not a easy task. This spike focusses on proposing a solution that would work for majority of the cases with parent-child pipelines and allow the possibility to iterate on the solution and also work seamlessly with multiple pipelines feature

Expected Outcomes

The goal of the spike is to find an efficient logic to select the source and target branch parent-child pipelines in an MR

Timebox: