fix: remove unnecessary breaking change in iproto code

Summary

• release: 5.1.0

• fix: remove unnecessary breaking change in iproto code

We don't want to introduce breaking changes for no reason

• fix: make the stored_procs_slice change less breaking

Ensure that

• New code is covered by tests
• API is documented
• Changelog is up to date
• Version is bumped in the appropriate Cargo.toml files