updateHeaderVisibility method
Updates the header visibility state reactively.
Implementation
void updateHeaderVisibility(String text, bool visible) {
final newVisibility = Map<String, bool>.from(headerVisibility)..[text] = visible;
final newAdditional = Map<String, dynamic>.from(value.additional)
..['headerVisibility'] = newVisibility;
updateState(
who: 'updateHeaderVisibility',
additional: newAdditional,
);
}