fix(label-title-only): allow hidden labels

[macjohnny]

take into account labels with aria-hidden="true" when evaluating the label-title-only rule.

Closes issue:
fixes #3174

[CLAassistant]

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[straker]

I'm wondering if we should instead update the labelVirtual code to no check if the aria-labelledby element is visible. I'll get back to you once I've had a chance to talk to @WilcoFiers about it.

[macjohnny]

@straker

I'm wondering if we should instead update the labelVirtual code to no check if the aria-labelledby element is visible. I'll get back to you once I've had a chance to talk to @WilcoFiers about it.

I tried that as an alternative, however, the build failed when trying to use arialabelledbyText inside labelVirtual
Moreover, the doc states it only returns visible labels, which is why I went for the current solution.

[straker]

Alright, talked to Wilco and we decided that aria-hidden labels should pass, but visually hidden labels should not. That means we can just remove the true argument in the visualVirtual call in labelVirtual.

return vNode ? visibleVirtual(vNode) : '';

In conjunction with that change, we should update the description to the label-title-only rule to state what the rule is really looking for: that the element has a visual label.

    "description": "Ensures that every form element has a visible label and is not solely labeled using hidden labels, or the title or aria-describedby attributes",

[macjohnny]

Ok, will update the PR soon

[macjohnny]

@straker updated the PR according to your suggestions, please take a look :)

[straker]

Great! Thanks for the pr and the updates.

[straker]

Reviewed for security