Immediately open previous/next chapter on reader nav bar button click

The logic didn't handle cases were the next/previous chapter wasn't loaded yet, which lead to the load happening in the background without any user feedback.

src/modules/reader/components/viewer/ReaderViewer.tsx

@@ -161,7 +161,7 @@ const BaseReaderViewer = forwardRef(
         ref: ForwardedRef<HTMLDivElement | null>,
     ) => {
         const { direction: themeDirection } = useTheme();
-        const { resumeMode } = useLocation<ReaderOpenChapterLocationState>().state ?? {
+        const { resumeMode = ReaderResumeMode.START } = useLocation<ReaderOpenChapterLocationState>().state ?? {
             resumeMode: ReaderResumeMode.START,
         };