LPS-43256 split dockbar items appear on the wrong side of the page

Hey @ipeychev

Here is an update for LPS-43256, an RTL issue.

The code I removed was added by a commit by Bruno Basto. When this commit was merged, it caused a lot of issues, and resulted in a lot of unneeded code in classic theme. From what I can see, this code doesn't serve a purpose anymore, and was causing the RTL issue with the add-controls.

The right:auto; I added is necessary for RTL when creating a new theme based off of _styled.

Please let me know if you have any questions.