[FIX] web_editor: spacing issue between columns of tablepicker

Issue:
======
The last column in `rtl` direction is connected to it's neighbor column.

Steps to reproduce the issue:
=============================
- Install notes and website
- Change language to arabic
- Go to notes and write `/` and opent eh table picker
- The last column (most left) is connected to it's neighbor

Origin of the issue:
====================
We forced the margin-right of the last cell in the row to have
`margin-right = 0` which is the case for `ltr` but not in `rtl`.

Solution:
=========
Use of `end` and `start` better to handle the direction
(https://developer.mozilla.org/en-US/docs/Web/CSS/margin-inline-start)

task-3825970

closes odoo/odoo#159643

X-original-commit: 0d57a30d12775d8c0ecdb6c3fab5ce191d3f2ccc
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>
Signed-off-by: Mahdi Cheikh Rouhou (macr) <macr@odoo.com>

addons/web_editor/static/src/js/editor/odoo-editor/src/style.scss

@@ -283,11 +283,11 @@
         width: 19px;
         height: 19px;
         padding: 0;
-        margin-right: 3px;
+        margin-inline-end: 3px;
         margin-bottom: 3px;
 
         &:last-of-type {
-            margin-right: 0;
+            margin-inline-end: 0;
         }
         &.active {
             background-color: var(--oeTablepicker-color-accent, $o-brand-primary);