fix(deps): Update dependency @sanity/assist to v5

Author: renovate[bot]

packages/sanity-config/package.json

@@ -6,7 +6,7 @@
     ".": "./src/index.tsx"
   },
   "dependencies": {
-    "@sanity/assist": "^4.4.8"
+    "@sanity/assist": "^5.0.0"
   },
   "devDependencies": {
     "@repo/typescript-config": "workspace:*",