dismiss keyboard when scrolling after auto-search

// FREEBIE

Signal/src/ViewControllers/GifPicker/GifPickerViewController.swift

@@ -268,6 +268,12 @@ class GifPickerViewController: OWSViewController, UISearchBarDelegate, UICollect
         }
     }
 
+    // MARK: - UIScrollViewDelegate
+
+    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+        self.searchBar.resignFirstResponder()
+    }
+
     // MARK: - UICollectionViewDataSource
 
     public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {