chore: Drop unnecessary crossjoin allowances for DAST tables
What does this MR do and why?
chore: Drop unnecessary crossjoin allowances for DAST tables
These were added while tables were individually migrated but now these sibling tables all live under gitlab_sec.
Fixes Fix cross-join between dast_site_validations an... (#474985) and Remove cross database operations between dast_s... (#478563)
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