Button Block: Allow custom width

[prasadkarmalkar]

Issue: #62247

What?

Add FontSizePicker for button block for custom width size

Why?

To allow custom width for button block

How?

We are using the FontSizePicker for width of the button so that we can choose the custom size as well. And instead of giving width using class we are using the style attribute.

Testing Instructions

Testing Instructions for Keyboard

Screenshots or screencast

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: prasadkarmalkar <prasadkarmalkar@git.wordpress.org>
Co-authored-by: mirka <0mirka00@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[github-actions]

👋 Thanks for your first Pull Request and for helping build the future of Gutenberg and WordPress, @prasadkarmalkar! In case you missed it, we'd love to have you join us in our Slack community.

If you want to learn more about WordPress development in general, check out the Core Handbook full of helpful information.

[mirka]

Thank you for contributing! 🙌

Please see #62247 (comment) for a suggestion to use a more standard mechanism for this.