[Tests] pin eslint in type tests to ~9.38.0

eslint v9.39.0 introduced TS 4.1+ syntax in its bundled types, breaking TS 4.0 compatibility.

See eslint/eslint#20495

Author: ljharb

test-published-types/package.json

@@ -3,6 +3,6 @@
   "private": true,
   "version": "0.0.0",
   "dependencies": {
-    "eslint": "^9.11.1"
+    "eslint": "~9.38.0"
   }
 }