ToolbarItem - expand-all variant should include expand all icon

re: https://github.com/patternfly/patternfly-react/pull/9605/files

The expand all icon is currently something the user passes, but for us to mirror it automatically in RTL in the CSS, our component should be updated to include it for the user. This button is primarily for an expandable data-list and table, and the expand toggles in those components supply the icon, so the toolbar probably should, too, and would provide consistency in the icons used. We could probably do it a couple of ways:

1. Keep everything the way it is now, but update <ToolbarExpandIconWrapper> to include the icon for the user. And rename it to <ToolbarExpandAllIcon>? That aligns with the core class. IMO that should be updated whether we use it as a wrapper or not.
2. Update <ToolbarItem variant="expand-all"> to bundle the 1) toggle button, 2) <ToolbarExpandIconWrapper>/<ToolbarExpandAllIcon>, and 3) the icon. Chatting with @thatblindgeye, we could also allow tooltip props in case someone wants a tooltip for the button.

As far as I can tell, the data list and table do not allow the user to pass their own icon to the expandable toggle, so I don't know that we need to allow for that in the toolbar, either? If we do, there is a question of whether it should go in <ToolbarExpandIconWrapper>/<ToolbarExpandAllIcon> or not, which will rotate (when expanded) and mirror (in RTL) the icon the user passes.

My vote would be for the second option.

Jira Issue: PF-118

まず ToolbarItem の expand-all バリアントと ToolbarExpandIconWrapper の実装を調べ、次に data-list および table コンポーネントの展開可能なトグルと比較します。どの提案された API を使用するかを判断し、結果のアイコンが展開状態と RTL 状態で一貫していることを確認します。