Fixed test worlds for underwater simulation of DopplerVelocityLogSystem plugin

[sauk2]

🦟 Bug fix

Fixes #2344

Summary

Running the tests for DopplerVelocityLogSystem plugin results in a blank screen.

Command

  gz sim underwater_currents.sdf --verbose 2

Resulting blank screen

Solution

After adding the SceneBroadcaster plugin to the world SDF through the following lines

    <plugin
      filename="gz-sim-scene-broadcaster-system"
      name="gz::sim::systems::SceneBroadcaster">
    </plugin>

Running previous Command

  gz sim underwater_currents.sdf --verbose 2

Resulting simulation screen

Checklist

• [x] Signed all commits for DCO
• [ ] codecheck passed (See contributing)
• [ ] All tests passed (See test coverage)

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[sauk2]

@arjo129 I have pushed the changes in a separate PR #2373. Request you to take a look and provide feedback. If you prefer, you can close this PR.

[arjo129]

Thanks @sauk2! Closing in favor of #2373.