[FIX] web_editor, website: never indent/outdent list groups

The "comparisons" website snippet uses a list group with the class set
on a UL. In consequence, the web editor considers it as a regular list
and may try to outdent it, which is not the expected behavior with a
list group. This fix ensures that ULs with the `list-group` class cannot
be in/outdented.

closes odoo/odoo#32709

Signed-off-by: Pierre Paridans <pparidans@users.noreply.github.com>

addons/web_editor/static/src/js/wysiwyg/plugin/bullet.js

@@ -313,6 +313,10 @@ var BulletPlugin = AbstractPlugin.extend({
         if (!range) {
             return;
         }
+        // list groups shouldn't be outdented like regular lists
+        if ($(dom.ancestor(range.sc, dom.isList)).hasClass('list-group')) {
+            return;
+        }
 
         var self = this;
         var nodes = [];

addons/web_editor/static/tests/wysiwyg_keyboard_tests.js

@@ -2227,6 +2227,18 @@ var keyboardTestsComplex = [{
             start: "p:contents()[0]->1",
         },
     },
+    {
+        name: "in ul.list-group (div > p > text before): BACKSPACE at start",
+        content: '<div><p>1</p></div><ul class="list-group list-group-flush"><li class="list-group-item"><p><br></p></li></ul>',
+        steps: [{
+            start: "p:eq(1)->0",
+            key: 'BACKSPACE',
+        }],
+        test: {
+            content: '<div><p>1</p></div><ul class="list-group list-group-flush"><li class="list-group-item"><p><br></p></li></ul>',
+            start: "p:eq(1)->0",
+        },
+    },
 ];
 
 QUnit.test('Complex', function (assert) {