[alert-manager] Ignore already resolved alert from pod different than active alert in datastore
[alert-manager] Ignore already resolved alert from pod different than active alert in datastore

The problem was that alerts turn on and off when an app is pushed-to because prometheus sends
already resolved alerts from the old pod for ~15 mins.
This change will ignore the already resolved alerts from the old pod.

Bug: skia:9551
Change-Id: Ib0d110e604d942fcc9694465ea39c7746bbb68fa
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/250238
Commit-Queue: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

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