fix: remove invalid dropdown aria-expanded

[terminalchai]

This is the problem:

Choices renders invalid HTML for a simple text input because the dropdown wrapper gets an unsupported aria-expanded attribute.

Steps to reproduce:

1. Initialize Choices on a text input.
2. Inspect the rendered markup.
3. Validate the generated HTML and note the invalid aria-expanded usage on the dropdown wrapper.

This is my solution:

Remove aria-expanded from the dropdown wrapper and stop toggling it in the dropdown component, while keeping unit coverage aligned with the valid markup.

Testing

• npm run test:unit
• npm run lint

Closes #1016

[Xon]

As I understand it, this attribute should be added when the backing element is a select element as it opens a dropdown where in general the text element does not.

[Xon]

Removing aria-expanded will also break some of the css for select-one/select-multiple setups

[terminalchai]

Updated this to address the select-element concern:

• text-input dropdowns no longer receive or toggle aria-expanded
• select-one/select-multiple dropdowns keep the initial aria-expanded="false" and continue toggling it on show/hide
• added coverage for both text and select dropdown behavior

Tests run locally:

• npm run lint:js
• npx vitest run test/scripts/components/dropdown.test.ts test/scripts/templates.test.ts
• npm run test:unit