6e8da912601c222f0ebd22c1780bcfbc0903e948  AX: In a radio group with the required attribute on one button, the other buttons aren't exposed as required

Classified as not security-relevant.
Triage note: AccessibilityNodeObject::isRequired() and AXObjectCache now treat a radio button as required when any button in its radioButtonGroup is, propagating RequiredStatusChanged and queuing the IsRequired property. Accessibility correctness only; no security impact.
This commit was flagged by the signal scorer and reviewed by AI (not a human). It is listed only so the triage is auditable; there is no root-cause analysis because this is not a vulnerability fix.

Structural signals: smartptr_member_added (+4.87), surgical (+1.3)