Make `WalkthroughComponent.focusElement` public

[GerkinDev]

Hi,

I'm building a walkthrough where I expect users to do the interactions we guide them through. We focus some buttons, and expect them to click on them. For this, I've bound the WalkthroughContainerComponent.focusClick input (which seems to be incorrectly documented as focusAction), and propagate the event to the target element.

For this, I should either get the element by myself, which would be redundant, or access the _focusElement private property. Would it be possible to make this property public, or public readonly ?

Cheers ! :beers: