Align lease finalization validation flows (#53)

frontend/src/app/components/lease-finalization-page/lease-finalization-page.spec.ts

@@ -167,7 +167,9 @@ describe('LeaseFinalizationPage', () => {
 	});
 
 	it('keeps a finalization failure actionable without showing success', () => {
-		finalize.mockReturnValue(throwError(() => ({ error: { message: 'PDF signé refusé' } })));
+		finalize.mockReturnValue(
+			throwError(() => ({ status: 409, error: { message: 'PDF signé refusé' } })),
+		);
 		const fixture = TestBed.createComponent(LeaseFinalizationPage);
 		fixture.detectChanges();
 		const request: FinalizeLeaseRequest = {