[bug] primary indexes are lost from staging to production

[R-K-H]

Dunno what happened here, but we're missing PKs which I stop gapped with creating unique indexes, but this isn't how the migration is supposed to work, so we need to improve the process when running migrations.

We may have missed a PK index migration, however not sure where that was lost.

Given we had indexer v4 it could exist there.