Remove `constructive` extension of button and remove it with more
generalized `.mw-ui-progressive` class and rely on progressive color.
Also make use of central mediawiki.UI's variable.less file.
Bug: T136209
Change-Id: I22f365419c41dd888824dbfeb4b3c995713ac5a5
EventLogging uses sendBeacon now so there is no danger of losing
clicks because the browser navigates away. (On modern browsers,
anyway; but we can live with being a little imprecise on older
browsers. We don't use link click stats much, anyway.)
Bug: T89533
Change-Id: Id83f60585d11f06610d8514c211f0116c60ea936
OptionWidget constructor now accepts a 'data' config option instead of
a separate 'data' parameter.
See I7ee78b6d.
Change-Id: Ie54e9db788cbe846cd2d173498c7fe17bafc126e