fix(striker-ui): skip empty keys when building Grid items

striker-ui/components/Grid.tsx

@@ -13,14 +13,14 @@ const Grid: FC<GridProps> = ({
     return items.map(([itemId, itemGridProps], index) => {
       const key = itemId;
 
-      return (
+      return itemGridProps ? (
         <MUIGrid
           {...calculateItemBreakpoints(index, key)}
           key={key}
           item
           {...itemGridProps}
         />
-      );
+      ) : undefined;
     });
   }, [calculateItemBreakpoints, layout]);
 

striker-ui/types/Grid.d.ts

@@ -1,5 +1,5 @@
 type GridLayout = {
-  [id: string]: import('@mui/material').GridProps;
+  [id: string]: import('@mui/material').GridProps | undefined;
 };
 
 type GridOptionalProps = {