[CI] Enable full system test for gRPC frontend

Description

This commit enables the full system tests to run in CI with the grpc frontend, including the cta-admin commands implementation in grpc.

It updates the preset values for grpc to use the right endpoint for the grpc frontend in the cli and client pods.

It also renames the cta-admin-grpc executable to cta-admin after installing it in both pods, to allow seamless integration with the current test setup that expects an executable named cta-admin.

Checklist

• Documentation reflects the changes made.
• Merge Request title is clear, concise, and suitable as a changelog entry. See our contributing docs

References

Closes #363 (closed)