fix(ui): restore memory usage centering in sidebar after MUI v9 migration

The MUI v9 migration moved boxStyle layout props into sx, but the memory
usage Box had a separate sx that overwrote it. Merge boxStyle.sx like the
upload/download rows already do.

src/components/layout/layout-traffic.tsx

@@ -131,6 +131,7 @@ export const LayoutTraffic = () => {
               title={`${t('home.components.traffic.metrics.memoryUsage')} `}
               {...boxStyle}
               sx={{
+                ...boxStyle.sx,
                 cursor: 'auto',
                 // opacity: memory?.is_fresh ? 1 : 0.6,
               }}