chore: captcha input dx tweaks

[stevehobbsdev]

Changes

This PR provides some tweaks to the Captcha input, mostly for dev experience and my own sanity.

• Remove mask-type on the refresh icon - the linter always complains about this and they're investigating whether to support it or not. Doesn't appear to affect the icon visually (see screenshot), so it's been removed for now.
• Rework the function binders to use arrow syntax; VSCode just doesn't support the "::" syntax for function binding and produces syntax errors in my editor, causing formatters and things to not work.
• Separately, removes IE11 from the BS testing Matrix. These have been verified locally, and the BS runner continues to be unreliable in this area.

Testing

• This change adds unit test coverage
• This change adds integration test coverage
• This change has been tested on the latest version of the platform/language

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All code quality tools/guidelines have been run/followed
• All relevant assets have been compiled