Nested items in draggable tables are dragged in the opposite left/right direction in RTL

[klonos]

Description of the bug
It seems that we have somehow missed https://www.drupal.org/project/drupal/issues/197641

Steps To Reproduce

1. Enable the Language core module
2. Add an RTL language (Arabic or Hebrew for example), and set that as the site default -> this should switch the site to RTL
3. Navigate to a page with some nested draggable items (taxonomy terms or menu items).

Actual behavior
Drag an item to the left -> it is dragged to the right 👎
Drag an item to the right -> it is dragged to the left 👎

Expected behavior
Nested draggable items should be dragged to the correct left/right direction.

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PR by @klonos: backdrop/backdrop#2529

[herbdool]

@klonos we should also include this https://www.drupal.org/project/drupal/issues/197641#comment-10396111 as commenter noticed an issue with 2 levels deep.

[herbdool]

Tested and it looks good. 2+ levels deep.

[quicksketch]

Padding here is still a little off:

LTR:

RTL:

Seems like it's the generic padding on [dir="rtl"] ul that may be causing the problem. We may need to add [dir="rtl"] .ckeditor-active-toolbar-configuration { padding: 0; margin: 0; }. Even though it's not different from RTL to LTR, the specificity of [dir="rtl"] ul is winning over the .ckeditor-active-toolbar-configuration selector.

[klonos]

@quicksketch we know, but this is the wrong issue 😛: #3504

Setting this back to RTBC.

[quicksketch]

Oops! I'm sorry! I'll take another look at this one and make sure I'm looking at the right thing. 😅

[quicksketch]

Okay, now looking at the right PR, looks great! Thanks @klonos and @herbdool! Merged backdrop/backdrop#2529 into 1.x and 1.12.x.