chore(contracts): update Viper OpenAPI pin

[github-actions]

Scheduled drift check detected a change in the live Viper OpenAPI spec.

Source: https://viper-xi.vercel.app/api/openapi.json

oasdiff exit code: 0 (1 = breaking changes for assets-processIntegrationCreate)

oasdiff output:

No changes detected
::notice::Non-breaking Viper OpenAPI changes:
No changes detected
No breaking Viper OpenAPI changes detected

Automated by contracts.yml drift job.

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Summary by cubic

Update the Viper OpenAPI pin to match the current live spec in contracts/viper/openapi.json. No breaking changes detected by oasdiff.

^{Written for commit 78494e9. Summary will update on new commits.}