"role attribute has valid value" (674b10): Replace 'included in the accessibility tree' with 'hidden state is false'

[Jym77]

Replace "included in the accessibility tree" requirement, which was causing some weird issues with containers, with "whose hidden state is false".

Closes issue(s):

• closes "role attribute has valid value" (674b10): Failed Example 1 and 2 are incorrect #1551

Need for Final Call:
This will require a 1 week Final Call (small change in Applicability)

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[Jym77]

Call for review ends on June 17th.

[Jym77]

Call for review has ended. Merging.