Fix milestone labels on migration files
What does this MR do and why?
!159649 (merged) was merged right after the cutoff for %17.3, so the migrations will be packaged in %17.4 and we need to update the designation to reflect that.
!159649 (merged) was merged right after the cutoff for %17.3, so the migrations will be packaged in %17.4 and we need to update the designation to reflect that.