Fix crash when running the optical tactile sensor world

[iche033]

🦟 Bug fix

Summary

Fix crash that happens when the optical tactile plugin loads SDF Element parameters.

Updated to read parameters differently:

• The sensor's update rate field should be available so skipped the check
• The sensor topic can be can be found in the SensorTopic component. If for some reason it's empty, get it from the Sensor DOM object.

Checklist

• [x] 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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