fix(router): l2 cache uses client name in key, persisted operation not found returns 200

[df-wg]

Motivation and Context

Previous PRs added APQ, and affected persisted operations. This PR makes two changes:

• It closes Incorrect ClientInfo Handling When Loading Persisted Operations from Cache #1179, ensuring that different client names can't access different users persisted operations
• It ensures that even when a persisted operation isn't found, it'll return 200, since it's a well formed GraphQL query

Checklist

• I have discussed my proposed changes in an issue and have received approval to proceed.
• I have followed the coding standards of the project.
• Tests or benchmarks have been added or updated.
• Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• I have read the Contributors Guide.