Remove unecessary subdata for unpadded attachment

// FREEBIE

SignalServiceKit/src/Util/Cryptography.m

@@ -351,17 +351,17 @@ const NSUInteger kAES256_KeyByteLength = 32;
 
         if (unpaddedSize == paddedPlainText.length) {
             DDLogInfo(@"%@ decrypted unpadded attachment.", self.tag);
+            return [paddedPlainText copy];
         } else {
             unsigned long paddingSize = paddedPlainText.length - unpaddedSize;
             DDLogInfo(@"%@ decrypted padded attachment with unpaddedSize: %u, paddingSize: %lu",
                 self.tag,
                 unpaddedSize,
                 paddingSize);
-        }
-
             return [paddedPlainText subdataWithRange:NSMakeRange(0, unpaddedSize)];
         }
     }
+}
 
 + (unsigned long)paddedSize:(unsigned long)unpaddedSize
 {