[FIX] web_editor: adapt options' icons in RTL

The triangle pointing towards an option in the editor is pointing
right and the symbol └ is used to show a sub option in the editor panel.
In a RTL setting, this does not make sense and should be mirrored.

task-3284274

closes odoo/odoo#125091

X-original-commit: f65a9bff
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/web_editor/static/src/scss/wysiwyg_snippets.scss

@@ -273,6 +273,10 @@
                       // browser default font, we should use a SVG instead.
         display: inline-block;
         margin-right: 0.4em;
+
+        .o_rtl & {
+            transform: scaleX(-1);
+        }
     }
     @for $level from 1 through 3 {
         .o_we_sublevel_#{$level} {
@@ -1647,7 +1651,12 @@
                     content: '\f0da';
                     position: static;
                     transform: none;
+
+                    .o_rtl & {
+                        transform: scaleX(-1);
+                    }
                 }
+
                 &.active {
 
                     &::after {