Correctly load smoothing plugins in Servo integration tests

[sea-bass]

Description

I just realized in analyzing servo integration tests that they were pulling from the panda_simulated_config.yaml (which currently uses the Acceleration filter plugin), but still had the old parameters from the Butterworth filter plugin in the launch files.

As a consequence, the smoothing plugin was not loading correctly in these tests; see, e.g., this CI run.

This happens specifically because the Acceleration filter parameters do not have defaults, so they are required. Butterworth, on the other hand, has a default parameter value for its one coefficient.

@AndyZe FYI if you are switching the default in panda_simulated_config.yaml to the new Ruckig plugin in your PR, you will need to make similar updates in the integration test launch files as well.

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers