Pipeline Mini Graph clean up

What does this MR do and why?

This MR resolves 2 tasks from #473900

• Keep latest downstream pipelines (bug)
• Report all queries to sentry

Screenshots or screen recordings

No UI change

How to set up and validate locally

Prerequisites

• An enabled feature flag: Feature.enable(:ci_graphql_pipeline_mini_graph)
• A working runner

Steps

1. Navigate to a project (this example uses the flightjs group)
2. Navigate to the Pipeline Editor (Build > Pipeline editor)
3. Update the gitlab-ci.yml and add a bridge job

bridge_job:
  trigger:
    include: child-pipeline.yml

child-pipeline.yml can live in the repo directory and have a simple script:

job:
  script: 
    - sleep 10

1. Run the pipeline
2. When the pipeline mini graph loads in the widget above (or in the commit page), retry the bridge job in the stage dropdown and insure that only one downstream pipeline renders.