Fix race condition in deleting scan result policy violation

What does this MR do and why?

Fixes a potential race condition while deleting Security::ScanResultPolicyViolation when a project has multiple inherited security policy project. delete_in_batches(project.scan_result_policy_violations) deletes all ScanResultPolicyViolation associated to a project, but we want to delete those only related to the Security::OrchestrationPolicyConfiguration

Query Plan

SELECT
    "scan_result_policy_violations"."id" 
FROM
    "scan_result_policy_violations" 
WHERE
    "scan_result_policy_violations"."scan_result_policy_id" IN (
        SELECT
            "scan_result_policies"."id" 
        FROM
            "scan_result_policies" 
        WHERE
            "scan_result_policies"."security_orchestration_policy_configuration_id" = 1027925 
            AND "scan_result_policies"."project_id" = 51803546
    )

 Nested Loop  (cost=0.71..9.79 rows=1 width=8) (actual time=11.242..11.247 rows=1 loops=1)
   Buffers: shared hit=4 read=6
   I/O Timings: read=10.966 write=0.000
   ->  Index Scan using index_scan_result_policies_on_position_in_configuration on public.scan_result_policies  (cost=0.43..3.45 rows=1 width=8) (actual time=9.239..9.241 rows=1 loops=1)
         Index Cond: ((scan_result_policies.security_orchestration_policy_configuration_id = 1027925) AND (scan_result_policies.project_id = 51803546))
         Buffers: shared hit=3 read=4
         I/O Timings: read=9.008 write=0.000
   ->  Index Scan using index_scan_result_policy_violations_on_policy_and_merge_request on public.scan_result_policy_violations  (cost=0.29..6.31 rows=3 width=16) (actual time=1.994..1.996 rows=1 loops=1)
         Index Cond: (scan_result_policy_violations.scan_result_policy_id = scan_result_policies.id)
         Buffers: shared hit=1 read=2
         I/O Timings: read=1.958 write=0.000

Time: 13.457 ms
  - planning: 2.129 ms
  - execution: 11.328 ms
    - I/O read: 10.966 ms
    - I/O write: 0.000 ms

Shared buffers:
  - hits: 4 (~32.00 KiB) from the buffer pool
  - reads: 6 (~48.00 KiB) from the OS file cache, including disk I/O
  - dirtied: 0
  - writes: 0

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.