`/usage` not working when resuming a session

### Describe the bug

I wanted to check the usage statistics of some of my previous sessions in copilot-cli using `/usage` when I noticed that for all of them it showed 0 premium requests and no per-model in/out token stats.

### Affected version

GitHub Copilot CLI 0.0.414.

### Steps to reproduce the behavior

1. In a currently active copilot-cli session execute the `/usage` command
2. `/exit` the session
3. `/resume` the session (or through `copilot --resume=...` and retry the `/usage` command

### Expected behavior

Premium requests and token usage are visible for old sessions as well.

### Additional context

Here's an example, in a currently active session:

After `/exit` and then resuming that session: