Fix zwave_js set config dropdown default value

[cgarwood]

Proposed change

With the switch from paper elements to <ha-select> the default value wasn't working in the Z-Wave JS Node Config panel. From what I could tell, the value was sometimes being parsed as an integer, while the
value of a list-item was being parsed as a string. So we're coercing all the values to a string.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[kpine]

Fixes home-assistant/core#67765.

[zsarnett]

Needs to run prettier