fix(deps): update material-ui monorepo to v7

Author: renovate[bot]

frontend-demo/package.json

@@ -21,8 +21,8 @@
     "@mitodl/open-api-axios": "^2025.4.8",
     "@mitodl/smoot-design": "^6.4.0",
     "@mui/lab": "^6.0.1-beta.34",
-    "@mui/material": "^6.1.8",
-    "@mui/material-nextjs": "^6.1.8",
+    "@mui/material": "^7.0.0",
+    "@mui/material-nextjs": "^7.0.0",
     "@remixicon/react": "^4.2.0",
     "@tanstack/react-query": "^5.74.3",
     "ai": "^4.0.25",