Fix/library continue read button causes page refresh (#521)

* Use app routing to open reader

Otherwise, the app loses the navigation history and won't open the last page (library) when closing the reader

* Prevent setting 0 as grid width

After the change of 4ebe6494f6c97c0d064c617f70b36682e6aedcb2, closing the reader and coming back to the library resulted in a single manga per row, due to the grids width being 0.

src/components/MangaGrid.tsx

@@ -223,7 +223,17 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
     );
 
     const updateGridWidth = () => {
-        setDimensions(gridRef.current?.offsetWidth ?? document.documentElement.offsetWidth);
+        const getDimensions = () => {
+            const gridWidth = gridRef.current?.offsetWidth;
+
+            if (!gridWidth) {
+                return document.documentElement.offsetWidth;
+            }
+
+            return gridWidth;
+        };
+
+        setDimensions(getDimensions());
     };
 
     useLayoutEffect(updateGridWidth, []);