[FR] CI Job to Sync ES|QL Custom Fields with Prebuilt Filterlist for Telemetry

### Repository Feature

Core Repo - (rule management, validation, testing, lib, cicd, etc.)

### Problem Description

At the moment, when using ES|QL for writing detection rule queries, often we use aggregate functions, eval or pre-processing functions (grok and dissect) to create useful fields for our filters.

In this instance, those fields are not available in global alert telemetry, which relies on a static filterlist for determining what fields to ingest from the alerts.

### Desired Solution

As such, we must develop a CI job that loads the ES|QL rules, reviews custom fields and adds those to the filterlist. The CI job would run on merges into main only.

### Considered Alternatives

No alternatives considered. This suggestion is post conversation with Security Data Analytics team.

### Additional Context

Related to https://github.com/elastic/ia-trade-team/issues/101