chore: revert libdatadog dep to published version 0.8.1

The GitHub SHA dep doesn't include prebuilt binaries, causing ENOENT
errors when tests try to load native addons.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tlhunter

package.json

@@ -138,7 +138,7 @@
     "import-in-the-middle": "^3.0.0"
   },
   "optionalDependencies": {
-    "@datadog/libdatadog": "DataDog/libdatadog-nodejs#0cc6fd6ae6d52714618291cb4021b618d13df152",
+    "@datadog/libdatadog": "0.8.1",
     "@datadog/native-appsec": "11.0.1",
     "@datadog/native-iast-taint-tracking": "4.1.0",
     "@datadog/native-metrics": "3.1.1",