fix(context): clear binding cache upon scope/getValue changes

[raymondfeng]

Extracted from #2635:

Make sure binding cache is cleared if the binding is bound to a new value provider or scope

• The binding instance may cache values for contexts based on the scope
• If an existing binding changes its value provider or scope, the cache should be invalidated.

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

[bajtos]

Thank you for this smaller pull request ❤️

I ran of time today, I'll review the changes in more detail tomorrow.

[bajtos]