🦟 Bug fix

Fixes #488

Summary

This PR adds parity with https://github.com/ros2/common_interfaces/blob/master/sensor_msgs/msg/NavSatFix.msg message.
For completeness it also adds the velocity DOP.

Disclamer: I have no idea how this actually integrates with the rest of gazebo, and I couldn't find much info, so I would thank you if you tell me where I would need to add code to make it work with the gz ros2 bridge.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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