[Security Solution] Increase parallelism for slow Rule Management test groups

[banderror]

PR 1: #234930
PR 2: #235729

Summary

Some of our test groups have been running for too long, sometimes exceeding 40 minutes and more. We should look into applying parallelism to them like it was done in #230969.

The list of problematic test groups:

• x-pack/test/security_solution_api_integration/test_suites/detections_response/rules_management/prebuilt_rules/customization_enabled/configs/ess.config.ts: 41.5 minutes
• x-pack/test/security_solution_api_integration/test_suites/detections_response/rules_management/prebuilt_rules/customization_enabled/configs/serverless.config.ts: 41 minutes
• x-pack/solutions/security/plugins/security_solution/public/detection_engine/rule_management_ui/pages/rule_management/integration_tests/rules_upgrade/upgrade_rule_after_preview/common_fields/jest.integration.config.js: 45.3 minutes, 71.2 minutes, 98 minutes
• x-pack/solutions/security/plugins/security_solution/public/detection_engine/rule_management_ui/pages/rule_management/integration_tests/rules_upgrade/upgrade_rule_after_preview/type_specific_fields/jest.integration.config.js: 41 minutes

PRs

• [Security Solution] Parallelize slow Rule Management tests #234930
• [Security Solution] Fix MKI pipeline after splitting Rule Management tests #235729

[elasticmachine]

Pinging @elastic/security-detections-response (Team:Detections and Resp)

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[elasticmachine]

Pinging @elastic/security-detection-rule-management (Team:Detection Rule Management)