fix: message shouldnt be clikced while loading (#142)

fixes: https://sendbird.atlassian.net/browse/UIKIT-1684
Co-authored-by: Sravan S <sravan@sendbird.com>

Author: sravan-s

src/ui/FileViewer/index.jsx

@@ -144,7 +144,7 @@ export default function FileViewer(props) {
     onDelete,
   } = props;
   const {
-    sender,
+    sender = {},
     type,
     url,
     name = '',

src/ui/ThumbnailMessageItemBody/index.tsx

@@ -34,7 +34,11 @@ export default function ThumbnailMessageItemBody({
         mouseHover ? 'mouse-hover' : '',
         message?.reactions?.length > 0 ? 'reactions' : '',
       ])}
-      onClick={() => showFileViewer(true)}
+      onClick={() => {
+        if(message?.sendingStatus === 'succeeded'){
+          showFileViewer(true);
+        }
+      }}
     >
       <ImageRenderer
         className="sendbird-thumbnail-message-item-body__thumbnail"