Add missing reference to ros_gz_image per #432

[ShubhkarmanSingh7]

📝 Documentation Update

Addresses #432

Summary

The ROS 2 Integration overview page was missing references to the specialized image transport packages. This PR adds a brief section highlighting ros_gz_image for heavy sensor data transport.

(Note: Per @azeey's comment on the issue regarding ros_gz_pointcloud being broken and needing a component rewrite, I have intentionally excluded it from this PR to avoid pointing users to a broken package).

Checklist

• Signed all commits for DCO
• Added a screen capture or video to the PR description that demonstrates the feature
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed
• All tests passed
• Updated Bazel files (if adding new files). Created an issue otherwise.
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