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

Beginne mit der Untersuchung der expand-all-Variante von ToolbarItem und der Implementierung von ToolbarExpandIconWrapper. Vergleiche sie anschließend mit den erweiterbaren Toggles in den data-list- und table-Komponenten. Kläre, welche der vorgeschlagenen APIs verwendet werden soll, und überprüfe, dass das resultierende Icon in erweiterten und RTL-Zuständen konsistent ist.