fix: add rounded corners to Echarts visualization

Added rounded-md class to Echarts container to match the border radius styling of the visualization block.

Author: vieiralucas

apps/web/src/components/v2Editor/customBlocks/visualizationV2/VisualizationView.tsx

@@ -458,7 +458,7 @@ function Echarts(props: EchartsProps) {
           pointerEvents: 'none',
         }}
       />
-      {isReady && <div ref={ref} className="w-full h-full" />}
+      {isReady && <div ref={ref} className="w-full h-full rounded-md overflow-hidden" />}
     </>
   )
 }