Non-generic WithMany with string navigation name does not validate navigation exists

[ajcvickers]

 modelBuilder.Entity<Post>().HasMany(x => x.Tags)
                .WithMany("Posts")
                .UsingEntity<PostTag>(
                    j => j.HasOne(x => x.Tag).WithMany().HasForeignKey(x => x.TagId),
                    j => j.HasOne(x => x.Post).WithMany().HasForeignKey(x => x.PostId)
                );

Split off from #23717.

[anranruye]

It seems that you can close #23362 which is actually the same issue.