fix(ios): add a null exception protection to imageView blur process (Tencent#4530)

Author: wwwcg

renderer/native/ios/renderer/component/image/HippyImageView.m

@@ -118,6 +118,9 @@ static BOOL HippyImageNeedsShrinkForSize(UIImage *inputImage, CGSize size) {
 
         // copy image data
         dataSource = CGDataProviderCopyData(CGImageGetDataProvider(imageRef));
+        if (dataSource == NULL) {
+            return inputImage;
+        }
         memcpy(buffer1.data, CFDataGetBytePtr(dataSource), bytes);
         CFRelease(dataSource);
         dataSource = NULL;