[EuiBadge] Support onClick & href

[parkiino]

Type check fails when you have both an onClick prop and an href prop. Even if you are not using iconOnClick, if you have an href prop, type check requires iconOnClick and iconOnClickAriaLabel.

The EuiBadge type is inferred since type check knows it can't be an anchor because there's an onClick and it can't be a button because there's an anchor, so it must be the last type, which is iconOnClick+iconOnClickAriaLabel.

[chandlerprall]

@cchaos just to confirm, we want EuiBadge to work similarly to EuiButton and support both href & onClick props together?

[cchaos]

Yep, that's fine. I still like our ESLint warning, but we should still allow it for special cases.