fix(VBtn): accept value prop for underlying DOM element

[floroz]

Description

• Implements the logic to allow consumers to provide a value prop that will be attached as Node attribute to the underlying DOM element.

Motivation and Context

fix #16188

How Has This Been Tested?

Added Cypress Component testing

Types of changes

• 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 not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any features but makes things better)

Checklist:

• The PR title is no longer than 64 characters.
• The PR is submitted to the correct branch (master for bug fixes and documentation updates, dev for new features and backwards compatible changes and next for non-backwards compatible changes).
• My code follows the code style of this project.
• I've added relevant changes to the documentation (applies to new features and breaking changes in core library)

[floroz]

If these changes are fine, I'd be happy to also tackle the group:selected event which seems to have an incorrect signature, since it set to only emit true but never invoked upon click.

I assume the correct behaviour should be to emit the props.value ad added in the onClick

NVM, just learned about undocumented getCurrentInstance Vue API :)

[nekosaur]

If these changes are fine, I'd be happy to also tackle the group:selected event which seems to have an incorrect signature, since it set to only emit true but never invoked upon click.

I assume the correct behaviour should be to emit the props.value ad added in the onClick

That emit declaration is correct iirc. It is emitted from the useGroupItem composable

[floroz]

Thanks for the detailed feedback @johnleider.

I've polished the PR and implemented your suggestions.