Staging pipeline is creating "maestro managed feeds" which end up being picked up during dependency updates

Migrated from https://github.com/dotnet/core-eng/issues/14781

@riarenas wrote:

From [feedback in the First responders channel](https://teams.microsoft.com/l/message/19:afba3d1545dd45d7b79f34c1821f6055@thread.skype/1635287459740?tenantId=72f988bf-86f1-41af-91ab-2d7cd011db47&groupId=4d73664c-9f2f-450d-82a5-c2f02756606d&parentMessageId=1635287459740&teamName=.NET%20Core%20Eng%20Services%20Partners&channelName=First%20Responders&createdTime=1635287459740)
Dependency updates are bringing in a lot of isolated feeds for the same SHA during dependency update PRs.


There was only one build for that SHA of aspnetcore, https://dev.azure.com/dnceng/internal/_build/results?buildId=1437781&view=results but the staging pipeline adds additional locations and creates additional feeds that follow the same naming pattern that maestro uses. When maestro is creating a dependency update PR, it will find all these additional locations and feeds, and flow them to repos even though they are not really necessary, as all the feeds have the exact same assets in them.

@mmitche suggests:

> It's mainly annoying more than anything else. I suggest changing Maestro to either choose only the newest managed feed, or changing the staging pipeline such that the feed names don't match the Maestro managed feed pattern. The latter might make more sense, since it means we could create more representative feed names.

Both options seem sensible to me, and we might want to end up doing both anyways? I can't recall right now if there's a reason why it needs to pick up all the feeds instead of just one of them.