Write plan_name uids

What does this MR do and why?

This is MR 1 of 3 for the transition from plan_id to plan_name_uid.

1. [this MR] Start writing *plan_name_uid columns on create/update. Note: columns were added in !213444 (merged)
2. Backfill columns
3. Switch application logic to use uids.

References

• #571421

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