Refactor Flaky Tracker CI Script

Refactor Flaky Tracker CI Script

Overview

Refactor the existing flaky tracker CI script located at https://gitlab.com/gitlab-org/container-registry/-/tree/master/cmd/internal/flake-tracker to improve code organization and functionality.

Tasks

1. Extract Test Report Parsing

• Split the test report parsing logic into its own dedicated package
• Improve separation of concerns and code maintainability
• Ensure better code understanding and modularity

2. Implement Test Exclusion Feature

• Add functionality to exclude specific tests from flaky tracking
• Design and implement exclusion configuration mechanism

3. Fix Subtest Flaky Marking Logic

• Modify logic to avoid marking entire test suites as flaky when only subtests fail

4. Move slack notifications from #g_container-registry to #g_container-registry_alerts