Fix library search result rendering

ReactList may call itemRenderer with an index larger than list length
when the component is being updated. Failing to handle the case causes
the rendering to break due to an unhandled exception.

For example, try searching for "audioq". Until one types "audio",
search results are correctly narrowed, but typing the final letter
"q" does not update the results to zero due to an unhandled exception.

This patch fixes the issue by handling out of band indices in
itemRenderer.

Fixes #1109

Author: nya3jp

src/views/app/components/LibraryManager.tsx

@@ -137,6 +137,10 @@ class LibraryManager extends React.Component<ILibraryManagerProps, ILibraryManag
         const isOperating = !!this.props.installingLibraryName || !!this.props.uninstallingLibraryName;
 
         const itemRenderer = (index, key) => {
+            // On updating a list, ReactList can call itemRenderer with large indices.
+            if (index >= filteredLibraries.length) {
+                return null;
+            }
             return (<LibraryItemView key={filteredLibraries[index].name} library={filteredLibraries[index]} {...libraryItemProps}/>);
         };
         const itemSizeEstimator = (index, cache) => {