/update re-prompts with original -i "<prompt>"

[parth21999]

Describe the bug

I started a copilot session with -i "". I ran /update. After updating, the original got reinserted.

Affected version

GitHub Copilot CLI 1.0.39.

Steps to reproduce the behavior

I started a copilot session with -i "". I ran /update. After updating, the original got reinserted.

Expected behavior

Prompt should not be reinserted.

Additional context

No response