test(sheets): give the mocked sheet its dirty check

The capture picker and the mood page import `sheetBodyHasUnsavedInput`
from the sheet module now, and two tests that replace that module with
a stub failed on the missing export.

src/components/layout/__tests__/capture-picker.test.tsx

@@ -33,6 +33,7 @@ vi.mock("@/components/ui/responsive-sheet", () => ({
     open: boolean;
     children: React.ReactNode;
   }) => (open ? <section>{children}</section> : null),
+  sheetBodyHasUnsavedInput: () => false,
 }));
 
 vi.mock("@/components/dashboard/quick-entry-forms.lazy", () => ({