Refactor SAST & CodeQuality Inline Findings from REST to GraphQL

What does this MR do and why?

Second part to: #419177 (closed)

Refactor SAST & CodeQuality Inline Findings from REST to GraphQL

This commit is a piece of solving: #419177 (closed) It refactors the fetching of the CodeQuality Inline Findings and SAST findings from REST to GraphQl.

EE: true

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How to set up and validate locally

1. Enable sast_reports_in_inline_diff
2. Make sure your running an ultimate license or your GDK (how to)
3. Clone this repo: https://gitlab.com/jannik_lehmann/sast-inline-findings-example
4. Recreate this MR for SAST & CodeQuality findings: jannik_lehmann/cq-and-sast-test!5 (diffs)
5. Let the pipeline finish and the go checkout the diff page.

MR acceptance checklist

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