--[Bugfix] - Change assertion to just provide a user error if unused scale provided

[jturner65]

This PR changes an assertion that no scale is provided to the vertex-semantics mesh instantiation method to instead be a user error message, and removes an assertion that no lighting key be provided, but rather hardcodes the actual creation to be NO_LIGHT_KEY. Recent changes to allow for support of stage scaling have caused datasets that instantiate vertex-semantics meshes (like Replica) to unnecessarily fire this assertion. Besides, seems a bit extreme to assert on data being provided that is not even used.

Motivation and Context

How Has This Been Tested

Locally C++ and Python tests pass

Types of changes

• 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.

[0mdc]

LGTM!