ISBAT compare 'slug-like' strings across languages in Form block

**Describe the bug**
The From block has the ability to use Dynamic Subject lines by using shortcode replacements in the subject. The Form block currently does not process the shortcode into a 'slug-like' string yet it should both for programmatic comparison as well as visual placeholders. This fix will prevent undesirable aesthetics across international languages, namely those which use special characters.

**Visual display of shortcode placeholders should be slug-like across languages.**
https://github.com/godaddy-wordpress/coblocks/blob/0f75724b1f1a7f5d7772b2c53997601efb25b8a1/src/blocks/form/edit.js#L293-L305

**Programmatic comparison of shortcode slugs**
https://github.com/godaddy-wordpress/coblocks/blob/0f75724b1f1a7f5d7772b2c53997601efb25b8a1/includes/class-coblocks-form.php#L928-L958

**Possible technology to use: Lodash Kebab case**
https://lodash.com/docs/4.17.15#kebabCase