build(deps): bump fastify from 5.7.3 to 5.8.1 in /kms/auth-eth

Bumps [fastify](https://github.com/fastify/fastify) from 5.7.3 to 5.8.1.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v5.7.3...v5.8.1)

---
updated-dependencies:
- dependency-name: fastify
  dependency-version: 5.8.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

kms/auth-eth/package-lock.json

@@ -18,7 +18,7 @@
     "@openzeppelin/contracts-upgradeable": "^5.4.0",
     "dotenv": "^16.3.1",
     "ethers": "^6.13.5",
-    "fastify": "^5.7.3",
+    "fastify": "^5.8.1",
     "yargs": "^17.7.2"
   },
   "devDependencies": {