fix(desktop): add respondToApproval to clarify tool-part test mock

@assistant-ui/react 0.14 makes respondToApproval required on
ToolCallMessagePartProps; the settledClarifyProps helper still lacked it
after the upgrade cherry-picks, so tsc failed on clarify-tool.test.tsx.

apps/desktop/src/components/assistant-ui/clarify-tool.test.tsx

@@ -29,6 +29,7 @@ function settledClarifyProps(
     args,
     argsText: JSON.stringify(args),
     isError: false,
+    respondToApproval: vi.fn(),
     result,
     resume: vi.fn(),
     status: { type: 'complete' },