[Command] Add icon customization and fix inline styles

[ravisuhag]

Summary

Improvements to the Command component to fix typing and improve flexibility.

Improvements

2. No way to customize the search icon

CommandInput hardcodes MagnifyingGlassIcon. Should accept a custom icon or allow hiding it.

4. CommandShortcut doesn't accept ref as a prop

The only sub-component without ref prop support.

5. CommandDialog hardcodes inline styles

style={{ overflow: 'hidden', padding: '0' }} is hardcoded on Dialog.Content — should be CSS or overridable.

Moved to Cross-Cutting Issues

The following items have been moved to cross-cutting issues that address them across all components:

• Replace hardcoded CSS values with design tokens (Replace hardcoded CSS values with design tokens #672)
• TypeScript strictness (TypeScript strictness: eliminate any, @ts-ignore, and export prop types #675)