fix: remove unused SessionManager import in session.test.ts

Generated with [Continue](https://continue.dev)

Co-Authored-By: Continue <noreply@continue.dev>

Author: bdougie

extensions/cli/src/session.test.ts

@@ -16,7 +16,6 @@ import {
   updateSessionHistory,
   updateSessionTitle,
 } from "./session.js";
-import type SessionManager from "./session.js";
 
 // Mock dependencies first, before any imports
 vi.mock("os", () => ({