Simulator.reset should change default_lighting_key to point to scene instance lighting setup

[aclegg3]

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Motivation and Context

Moved this change from https://github.com/facebookresearch/habitat-sim/pull/2451 for closer evaluation in isolation and unit test updates.

How Has This Been Tested

CI TODO: requires changes to unit test GT images.

Types of changes

• [x] Docs change / refactoring / dependency upgrade
• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have completed my CLA (see CONTRIBUTING)
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[jturner65]

Changed this to merge into the dev branch