repl: Iterate on design of REPL sessions view (#14987)

This PR iterates on the design of the REPL sessions view.

We now use the same component for both available kernels and running
ones to provide some consistency between the two modes:

<img width="1208" alt="Screenshot 2024-07-22 at 6 49 08 PM"
src="https://github.com/user-attachments/assets/8b5c3600-e438-49fa-8484-cefabf4b44f1">

<img width="1208" alt="Screenshot 2024-07-22 at 6 49 14 PM"
src="https://github.com/user-attachments/assets/5125e9b3-6465-4d1e-9036-e6ca270dedcb">

Release Notes:

- N/A