Finalize DORA scores BG migration

As part of DORA Scores: Deployment frequency score is base... (#471741 - closed) a new batched background migration was introduced (Adds data migration to recalculate existing DOR... (!160259 - merged))to fix existing DORA performance scores.

The BG migration is already finished on SaaS (RecalculateDoraDeploymentFrequencyScore) so the only task left is to finalize the migration.