Add projectIds to ValueStreamStageMetrics resolver

Problem

Value stream stage metrics do not support filtering by project ID when using GraphQL. This does not match the functionality of the REST api currently used on the page.

Solution

In order to update the VSA frontend to GraphQL, we will need to add projectIds to group.valueStreams.stages.metrics:

{
  group(fullPath: "flightjs") {
    id
    valueStreams {
      nodes {
        stages(id: "gid://gitlab/Analytics::CycleAnalytics::Stage/19") {
          id
          name
          metrics(
+           projectIds: ["gid://gitlab/Project/7", "gid://gitlab/Project/24"]
            timeframe: {
              start: "2024-11-01",
              end: "2025-01-31"
            }
          ) {
            series {
              averageDurations {
                date
                value
              }
            }
          }
        }
      }
    }
  }
}

Related

This was attempted in !180785 (closed), but it was decided that some refactoring would be necessary to achieve the desired outcome (comment). The solution should ensure that the projectIds query param is only applicable for group namespaces.