fix(ask-sdk-core): type error in util

[igilham]

Fix a TypeError in the utility function getSupportedInterfaces.

Description

• Fix a TypeError in getSupportedInterfaces utility function.
• Add a test case to safeguard it from regressions.

Motivation and Context

This error occurs when calling getSupportedInterfaces with RequestEnvelopes for certain types of requests that do not provide the device property in the system context.

Fixes #709

Testing

Added a new unit test case calling the function with a mock RequestEnvelope which does not define the device property. In the existing code, the error is thrown. The behaviour in this patch is to return an empty object instead. This complies with the function's existing type signature so effects on clients should be minimal.

Types of changes

• [x] 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)
• [ ] Docs(Add new document content)
• [ ] Translate Docs(Translate document content)

Checklist

• [x] My code follows the code style of this project
• [ ] My change requires a change to the documentation
• [ ] I have updated the documentation accordingly
• [x] I have read the README document
• [x] I have added tests to cover my changes
• [x] All new and existing tests passed
• [x] My commit message follows Conventional Commit Guideline

License

• [x] By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[igilham]

Oops, that got closed as a result of a work-around PR in a private repository.