chore: bump etherpad-cli-client to ^4.0.3

4.0.3 sends author-attributed inserts and preserves the trailing
newline, complying with this PR's tightened USER_CHANGES validation.
The rate-limit CI workflow drives the test pad via this client, so
without the bump the new server-side rejects fire on the very first
\`pad.append()\` and the rate-limit disconnect never gets a chance to
arrive — testlimits.sh exits 0 instead of 1 and the rate-limit job
fails with "ratelimit was not triggered when sending every 99 ms".

Refs ether/etherpad-cli-client#131

Author: JohnMcLear

pnpm-lock.yaml

@@ -125,7 +125,7 @@
     "chokidar": "^5.0.0",
     "eslint": "^10.4.0",
     "eslint-config-etherpad": "^4.0.5",
-    "etherpad-cli-client": "^4.0.2",
+    "etherpad-cli-client": "^4.0.3",
     "mocha": "^11.7.5",
     "mocha-froth": "^0.2.10",
     "nodeify": "^1.0.1",