Add SEP policy source to job options

What does this MR do and why?

Add SEP policy source to job options.

• Add sha and project_id to SEP-triggered jobs options, following the same pattern as PEP.

References

1. Scope policy job options under a single key (!208845 - merged)
2. Add PEP source to job options (!190625 - merged)
3. 👉 This one: Add SEP policy source to job options (!209673 - merged)
4. Add policy source claims to id_tokens (!211472)

How to set up and validate locally

1. Setup a project with a scan execution policy
2. Trigger a pipeline
3. Verify the policy job options include policy: { sha: '...', project_id: <spp_id> }

   Ci::Build.find(<id>).options

MR acceptance checklist

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Related to #459001