Fix border radius for labeled slider

[spacegaier]

Breaking change

Proposed change

So far the border-radius was applied to the whole ha-labeled-slider element, which meant that e.g. for the color temperature background only the lower right corner of the blue to orange background was affected. The radius for the other three corners had no effect.

With this PR the radius is now applied to the actual slider for a consistent look:

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