Add force argument to triggerEvent

[jrmlt]

I believe triggerEvent is too restrictive if it forbids all events on a form control with the disabled attribute. While the specification only mentions "click events" and MDN refers to "browsing events," all browsers currently allow mouse tracking events, such as mouseenter and mouseleave, to trigger on disabled controls. Additionally, there are events unrelated to user interaction, like transitionend and animationend.

Beyond known events, there's also the case of CustomEvent, which is entirely valid in browsers but is currently blocked by triggerEvent.

Maintaining a comprehensive list of forbidden or allowed events might not be practical or sustainable. However, I suggest providing testers with an option to trigger events on disabled elements if necessary.

This PR allows to bypass the availability check on a disabled form control using the force argument.