Update API Docs and test to show that "optional" takes precedence over "partial"

[nabdelgadir]

See #3309 (review).

• Explain in API docs that the "partial" option is overridden by the "optional" option.
• Test that partial is still overridden when it is set to false

Checklist

👉 Read and sign the CLA (Contributor License Agreement) 👈

• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

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[bajtos]

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