fix: win.closeFilePreview recreates panel when called twice (#45319)

* fix: close quick look during tests on macOS

* use longer delay 🤷

* fix: sharedPreviewPanel being recreated on close

* test: ensure preview panel gets closed

spec/api-browser-window-spec.ts

@@ -6256,6 +6256,7 @@ describe('BrowserWindow module', () => {
       w.previewFile(__filename);
       await setTimeout(500);
       expect(showCalled).to.equal(false, 'should not have called show twice');
+      w.closeFilePreview();
     });
   });