Adjusting to new xacros

[mikramarc]

Proposed changes

Adjusting autodetector to pass in new flags to work with new xacros. Some additional cleanup.

Checklist

Before posting a PR ensure that from each of the below categories AT LEAST ONE BOX HAS BEEN CHECKED. If more than one category is applicable then more can be checked. Also ensure that the proposed changes have been filled out with relevant information for reviewers.

Tests

• No tests required to be added. (For small changes that will be tested by CI/CD infrastructure).
• Added automated tests (if a new class is added (Python or C++), the interface of that class must be unit tested).
• Manually tested in simulation (if simulation specific or no hardware required to test the functionality).
• Manually tested on hardware (if hardware specific or related).

Documentation

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• Added documentation (For any new feature, explain what it does and how to use it. Write the documentation in a relevant space, e.g. Github, Confluence, etc).
• Updated documentation (For changes to pre-existing features mentioned in the documentation).

[giusebar]

we should check if vec size is 0 and return None?

[giusebar]

just assuming there might be an extreme case in which people are able to lunch a hand with no fingers (e.g. phantom). if that is not possible in the xacro launch then should be ok.