Closes #7145

Currently, terminal persistence is global, i.e. split configurations are
restored across all workspaces.

This PR changes it to per-workspace, so configurations are restored only
within the same workspace. Opening a new window will start with a fresh
terminal.


https://github.com/user-attachments/assets/d43fe747-9f28-4723-b409-e8dbb3a23912


Release Notes:

- Improved terminal reopening to be per workspace instead of global.