fix(TerminalModal): remove incorrect loadAddon assertion in mobile WebGL test

The test was checking that loadAddon was never called with any object,
but fitAddon and webLinksAddon are both objects that are legitimately
loaded. The WebglAddon constructor check is sufficient to verify that
WebGL is not loaded on mobile.

packages/dashboard/app/components/__tests__/TerminalModal.test.tsx

@@ -926,7 +926,6 @@ describe("TerminalModal", () => {
 
       // Import WebGL addon mock to get reference for assertions
       const webglModule = await import("@xterm/addon-webgl");
-      const loadAddonSpy = vi.spyOn(mockTerminalInstance, "loadAddon");
 
       render(<TerminalModal isOpen={true} onClose={mockOnClose} />);
 
@@ -938,8 +937,8 @@ describe("TerminalModal", () => {
       // WebGL addon constructor should NOT have been called
       expect(webglModule.WebglAddon).not.toHaveBeenCalled();
 
-      // loadAddon should NOT have been called with WebGL addon
-      expect(loadAddonSpy).not.toHaveBeenCalledWith(expect.any(Object));
+      // loadAddon is called with fitAddon and webLinksAddon (not WebGL) — verified by
+      // the WebglAddon constructor not being called above
     });
   });