Add desired_sharding_keys for DesignManagement Module

What does this MR do and why?

Adds Desired Sharding Keys to all design management related tables.

Upon merging this, Tenet scale team will generate backfill migrations to populate namespace_id in the desired tables.

Issues: Add and backfill namespace_id for design manage... (#458869 - closed), Add sharding key for design_management (#461330)

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