Update material-ui monorepo to v5.15.8

Author: renovate[bot]

examples/material-ui/package.json

@@ -9,8 +9,8 @@
   "dependencies": {
     "@emotion/react": "11.11.3",
     "@emotion/styled": "11.11.0",
-    "@mui/material": "5.15.7",
-    "@mui/styles": "5.15.7",
+    "@mui/material": "5.15.8",
+    "@mui/styles": "5.15.8",
     "@tanem/react-nprogress": "latest",
     "@types/jest": "29.5.12",
     "@types/node": "20.11.16",