[FIX] web_editor: properly insert character in empty nested list

Fix a bug that can be reproduced like so:
- Insert list
- Type char
- ENTER
- TAB
- Type char
The character gets inserted _after_ the `br` instead of replacing it.

closes odoo/odoo#34805

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

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

@@ -1885,6 +1885,9 @@ var HelperPlugin = AbstractPlugin.extend({
         // Create empty text node to have a range into the node
         if (range.sc.tagName && !dom.isVoid(range.sc) && !range.sc.childNodes[range.so]) {
             $(range.sc).append(invisible);
+            if (invisible.previousSibling && invisible.previousSibling.tagName === "BR") {
+                invisible.previousSibling.remove();
+            }
             range = this.context.invoke('editor.setRange', invisible, 0);
         }
 

addons/web_editor/static/tests/wysiwyg_keyboard_tests.js

@@ -811,6 +811,18 @@ var keyboardTestsChar = [{
             start: "b:contents(0)->1",
         },
     },
+    {
+        name: "'a' in empty li",
+        content: '<ul><li><p><br></p></li></ul>',
+        steps: [{
+            start: "p->1",
+            key: 'a',
+        }],
+        test: {
+            content: '<ul><li><p>a</p></li></ul>',
+            start: "p:contents(0)->1",
+        },
+    },
 ];
 
 QUnit.test('Char', function (assert) {
@@ -2239,6 +2251,25 @@ var keyboardTestsComplex = [{
             start: "p:eq(1)->0",
         },
     },
+    // List indent
+    {
+        name: "ENTER -> TAB -> a' at end of li > p (split -> indent -> write)",
+        content: '<ul><li><p>a</p></li></ul>',
+        steps: [{
+            start: "p:contents()[0]->1",
+            key: 'ENTER',
+        },
+        {
+            key: 'TAB',
+        },
+        {
+            key: 'a',
+        }],
+        test: {
+            content: '<ul><li><p>a</p></li><li class="o_indent"><ul><li><p>a</p></li></ul></li></ul>',
+            start: "p:eq(1):contents()[0]->1",
+        },
+    },
 ];
 
 QUnit.test('Complex', function (assert) {