default value for configuration should be an empty dict

[chollinger]

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• Primary Contact: Cory Hollinger

Purpose

The default value for the GREASE config global was None. This led to Errors when attempting to index with .get with a default value if the global config was inaccessible or not configured (such as when tests were run locally, as there should be no need for a configuration to be present for that). Making the default an empty dict fixes this issue, and is more correct in my opinion.

Expected Outcome

Global configuration defaults to an empty dict.

Checklist

• [ ] Maintainer Code Review

[abstract-base-method]

Nice catch my friend!