chore: bump @openzeppelin/defender-sdk-base-client

Bumps [@openzeppelin/defender-sdk-base-client](https://github.com/OpenZeppelin/defender-sdk) from 1.15.2 to 2.7.1.
- [Release notes](https://github.com/OpenZeppelin/defender-sdk/releases)
- [Commits](https://github.com/OpenZeppelin/defender-sdk/commits)

---
updated-dependencies:
- dependency-name: "@openzeppelin/defender-sdk-base-client"
  dependency-version: 2.7.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

packages/relay-signer/package.json

@@ -36,7 +36,7 @@
     "@ethersproject/properties": "^5.7.0",
     "@ethersproject/strings": "^5.7.0",
     "@ethersproject/logger": "^5.7.0",
-    "@openzeppelin/defender-sdk-base-client": "^1.15.0",
+    "@openzeppelin/defender-sdk-base-client": "^2.7.1",
     "amazon-cognito-identity-js": "^6.3.6",
     "axios": "^1.7.2",
     "ethers": "^6.9.0",