[Security Solution] Calculate and save `ruleSource.isCustomized` in API endpoint handlers

[jpdjere]

Epics: https://github.com/elastic/security-team/issues/1974 (internal), https://github.com/elastic/kibana/issues/174168

Summary

Implement calculation of ruleSource.isCustomized in all necessary endpoints that write the ruleSource field to prebuilt rules, and where fields can be customized, diverging from the base version from the Rule Asset.

The calculation and saving of the field should be done in the following endpoints:

• [ ] Update Rule - PUT /rules
• [ ] Patch Rule - PATCH /rules
• [ ] Bulk Update Rules - PUT /rules/_bulk_update
• [ ] Bulk Patch Rules - PATCH /rules/_bulk_update
• [ ] Import Rules - POST /rules/_import
• [ ] Perform Rule Upgrade - POST /prebuilt_rules/upgrade/_perform (Internal)

Extracted to other tickets:

• Bulk Actions - POST /rules/_bulk_action: with action Edit rules action
  • https://github.com/elastic/kibana/issues/187706

Background

Context from RFC:

• Calculating the isCustomized field - see table with scenarios for calculation of isCustomized
• Calculating isCustomized during bulk editing rules
• Calculating isCustomized when importing rules - see table with import scenarios and their respective isCustomized calculations

https://github.com/elastic/kibana/blob/269649a908745f7e06d5377f65a1afe99147332a/x-pack/plugins/security_solution/docs/rfcs/detection_response/prebuilt_rules_customization.md?plain=1#L559-L584

https://github.com/elastic/kibana/blob/b6e0f87900067d7ef6f69206a36226aee595867e/x-pack/plugins/security_solution/docs/rfcs/detection_response/prebuilt_rules_customization.md?plain=1#L817-L821

[elasticmachine]

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

[elasticmachine]

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

[elasticmachine]

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

[banderror]

@jpdjere @xcrzx Extracted bulk editing into https://github.com/elastic/kibana/issues/187706 and updated the description.