chore(rtdb-limit-child-nodes): cleanup dev dependencies

[HassanBahati]

Description

Cleans up build-time dependencies in rtdb-limit-child-nodes so they live in devDependencies instead of dependencies, and removes the prepare script.

Related Issues

Fixes #2657

Changes Made

• Moved rimraf, typescript, @types/node, and @types/express-serve-static-core from dependencies to devDependencies in rtdb-limit-child-nodes/functions/package.json
• Removed the prepare script from package.json (so the backend doesn’t trigger a build during npm install)
• Bumped extension version to 0.1.17 in extension.yaml
• Added CHANGELOG entry for 0.1.17: chore: cleanup dev dependencies

Testing Evidence

Tests Run (if applicable)

• Unit tests
• Integration tests
• Manual verification (package.json structure, version bump, CHANGELOG)

Additional Notes

• This is an experiment to see how the release pipeline behaves without the prepare script and with build tools in devDependencies.