Added a toolbar button to empty recycle bin

[cinqmilleans]

Resolved / Related Issues
On the Recycle Bin page, there is no button to empty the Recycle Bin.
However, there is a New button which is never used. #6686

Details of Changes
On the Recycle Bin page, replace the button "New" by "Empty".
This button is only active if the Recycle Bin is not empty.

We can easily do the same for other pages.
@winston-de, can you give your opinion on my way of doing things?

Validation
How did you test these changes?

• Built and ran the app
• Tested the changes for accessibility

[yaira2]

Looking good! I added a couple comments on things I think should be adjusted.

[cinqmilleans]

@yaichenbaum I applied the changes except showing the New button. I don't think showing it is a good idea. What does the community think?

[yaira2]

@yaichenbaum I applied the changes except showing the New button. I don't think showing it is a good idea. What does the community think?

I think it's best to avoid shifting the toolbar buttons.

[cinqmilleans]

@yaichenbaum What are we doing concretely?

[yaira2]

@yaichenbaum What are we doing concretely?

I think it's best to add the icons to the right of the toolbar for now and to add back the "new" button.

[cinqmilleans]

@yaichenbaum Ok for me. I would do that tomorrow.

[cinqmilleans]

@yaichenbaum It is commited.
I added a separator, hidden when there is no additional button. This code should make it easy to add more.
I put Visibility back instead of x: load. This caused an unpleasant visual effect, the button being active for a second before going gray when we reached an already empty Recycle Bin.

[yaira2]

LGTM