Update feature flags for new job definitions checksum

What does this MR do and why?

This MR updates feature flags for the new job definitions checksum algorithm. The new feature flag enables us to force the new algorithm on internal projects before the 109 partition switch, and for all projects when we reach the 109 partition.

This allows for a gradual rollout and validation of the new algorithm across the platform, ensuring stability before full deployment.

New rollout procedure:

• enable ci_job_definitions_new_checksum in incremental steps
• enable ci_job_definitions_force_new_checksum only for internal projects on .com and at 100% on staging.

This way we can test the new checksum before the switch of partitions.

References

Related to #588132, #588260

Screenshots or screen recordings

Before	After

How to set up and validate locally

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