PM-5075 - use the user skill summary table

[vas3a]

This pull request simplifies the MemberSearchService in member-search.service.ts by removing unnecessary initialization logic and refactoring how skill win and submission data are queried. The changes improve maintainability and performance by leveraging a precomputed summary table and streamlining the query structure.

Service Initialization Simplification:

• Removed the use of the OnModuleInit lifecycle hook and related asynchronous initialization logic for loading skill event and engagement source type IDs. The service no longer stores these IDs in instance variables.

Database Query Refactoring:

• Replaced the dynamic computation of skill win and submission statistics (previously using multiple CTEs and filters) with a direct query to the skills.user_skill_win_summary table, simplifying the SQL and reducing query complexity.
• Adjusted the join logic for filtering members: now conditionally joins user_match_data only if skills are specified, improving query efficiency when no skills are provided.