fix: minor fixes to capabilities table output

[rossiam]

• removed superfluous newlines from beginning of capability output
• minor cleanup and refactoring of utility functions to make them a little more testable
• display type for optional arguments to commands the same as required (except still add " (optional)"
• write unit tests for entire capabilities-utils file

Checklist

• I have read the CONTRIBUTING document
• Any required documentation has been added
• My code follows the code style of this project (npm run lint produces no warnings/errors)
• I have added tests to cover my changes

[changeset-bot]

🦋 Changeset detected

Latest commit: 5500aa9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@smartthings/cli	Patch

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