Resolve "Resolve cross DB transaction for dast_profiles with dast_scanner_profile and dast_site_profile tables"

What does this MR do and why?

The .allow_cross_joins_across_databases was temporary until dast_scanner_profile and dast_site_profile tables is also transitioned to gitlab_sec schema Although that hasn't occurred yet, this commit replaces the use of .allow_cross_joins_across_databases

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #483010 (closed)