Use PushRules::CreateUpdateService as sole entry point for PushRule Create/Update

What does this MR do and why?

Merge all PushRule updates to CreateUpdateService

• Add PushRules::BaseService to extend BaseContainerService to allow use of organization.
• Update Admin::PushRulesController to use PushRules::CreateUpdateService

References

Screenshots or screen recordings

Screen_Recording_2025-07-10_at_16.44.51

How to set up and validate locally

• Navigate to the admin area
• Click on Push Rules from the left menu
• Under Push rules, select some rules to create or update existing rules
• Everything should work as expected

MR acceptance checklist

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 #540295 (closed)