Adroit hand dense reward fixes

[7oponaut]

• fix hand-to-object dense reward component sign in adroit hand door, hammer, and relocate scenarios

Description

This PR fixes the hand-to-object dense reward component signs in the adroit hand door, hammer, and relocate scenarios.

The bugs cause the agent to maximize distance between the hand and the object of interest.

The bugs were introduced in 7b5aa90 with a refactor of the relevant code sections. I ran trainings before and after the fix to confirm that it works.

As far as I can tell the pen scenario is not affected, so no changes there.

I couldn't find the relevant CONTRIBUTING.md file to set stuff up for precommit and unit testing.

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

Checklist:

• [ ] I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes