Added database reliability squad to standing squads issue labels to reduce triage and improve intentional assignment.

Why is this change being made?

The ~Squad::Database label was missing from the squad labels table. This MR is to add it so that Database Reliability labels get added by people following the process rather than being picked up in triage later. This should reduce the time to triage and resolve as requests get routed to the correct team intentionally.

Author Checklist

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