Hook up filters to API where availiable

[Mbeaulne]

Description

Implemented support for advanced pipeline run filters with a new JSON-based filter format while maintaining backward compatibility with the legacy key:value format. This change enables the pipeline run filters bar feature flag to be more than just a UI preview.

Type of Change

• New feature
• Improvement
• Refactor

Checklist

• I have tested this does not break current pipelines / runs functionality
• I have tested the changes on staging

Test Instructions

1. Enable the "pipeline-run-filters-bar" feature flag
2. Verify that the "Created by" filter works correctly in both the new UI and via URL parameters
3. Test that both JSON format filters and legacy key:value format filters work in the URL
4. Confirm that only supported filters (currently only "created_by") are sent to the API

Additional Comments

This PR adds a new utility file pipelineRunFilterUtils.ts that handles parsing and serializing filter formats. The flag description has been updated to clarify that only the "Created by" filter is currently functional, while other filters are UI previews that will be connected to the API in future PRs.

[Mbeaulne]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Hook up filters to API where availiable #1712 👈 (View in Graphite)
• Add BetaFeatureWrapper and pipeline run filters bar UI #1711
• Filter Bar #1708 : 1 other dependent PR (#1709 )
• Add created by me filter #1713
• Status filter #1707
• Annotation Filter input #1706
• Date picker #1705
• Add useRunSearchParams hook for pipeline run filtering #1704
• master

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