Accessibility: Explicitly implement protocols

This change is intended to resolve an issue where iOS apps failed
automated review due to use of non-public selectors. Explicitly adopting
the relevant protocols allowed an app to pass automated review during
testing.

modules/juce_gui_basics/native/accessibility/juce_ios_Accessibility.mm

@@ -225,8 +225,11 @@ static Holder create (AccessibilityHandler& handler)
  addMethod (@selector (accessibilityDataTableCellElementForRow:column:), getAccessibilityDataTableCellElementForRowColumn);
  addMethod (@selector (accessibilityRowCount), getAccessibilityRowCount);
  addMethod (@selector (accessibilityColumnCount), getAccessibilityColumnCount);
+ addProtocol (@protocol (UIAccessibilityContainerDataTable));
+
  addMethod (@selector (accessibilityRowRange), getAccessibilityRowIndexRange);
  addMethod (@selector (accessibilityColumnRange), getAccessibilityColumnIndexRange);
+ addProtocol (@protocol (UIAccessibilityContainerDataTableCell));
  }
  #endif