[FIX] web_editor: prevent closestElement traceback with comment nodes

Comment nodes don't have a `closest` method so when passing one to
`closestElement`, the method crashed.

----

Step to reproduce in website:
- Go to debug mode and to website app
- Click on configuration > websites
- Select a website and in the `custom_code_footer` field add an HTML
  comment
- Go to the website and try to enter edit mode -> Crash

The same error will be visible if you simply enter edit mode and drag &
drop the "Code" snippet and enter an HTML comment inside it.

-----

Step to reproduce in marketing automation:
- Install marketing automation
- Click on a campaign > Add a new activity
- On the mail template field, type something > Create and edit
- Select plain text -> `element.closest is not a function`

----

task-3083797
opw-3081323
opw-3081278

closes odoo/odoo#107486

X-original-commit: 3a9177dd6a6f12f75d0df8146b692e3486f2467c
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js

@@ -1885,7 +1885,7 @@ export class OdooEditor extends EventTarget {
         }
         if (joinWith) {
             const el = closestElement(joinWith);
-            fillEmpty(el);
+            el && fillEmpty(el);
         }
     }
 
@@ -3462,9 +3462,14 @@ export class OdooEditor extends EventTarget {
      */
     isSelectionInEditable(selection) {
         selection = selection || this.document.getSelection();
-        return selection && selection.anchorNode &&
-            closestElement(selection.anchorNode).isContentEditable && closestElement(selection.focusNode).isContentEditable &&
-            this.editable.contains(selection.anchorNode) && this.editable.contains(selection.focusNode);
+        if (selection && selection.anchorNode && selection.focusNode) {
+            const anchorElement = closestElement(selection.anchorNode);
+            const focusElement = closestElement(selection.focusNode);
+            return anchorElement && anchorElement.isContentEditable && focusElement && focusElement.isContentEditable &&
+                this.editable.contains(selection.anchorNode) && this.editable.contains(selection.focusNode);
+        } else {
+            return false;
+        }
     }
     /**
      * Returns true if the current selection is in at least one block Element

addons/web_editor/static/src/js/editor/odoo-editor/src/utils/utils.js

@@ -284,16 +284,17 @@ export function getFurthestUneditableParent(node, parentLimit) {
  *
  * @param {Node} node
  * @param {string} [selector=undefined]
- * @param {boolean} [restrictToEditable=false]
  * @returns {HTMLElement}
  */
 export function closestElement(node, selector) {
-    const element = node.nodeType === Node.TEXT_NODE ? node.parentElement : node;
-    if (selector && element) {
-        const elementFound = element.closest(selector);
-        return elementFound && elementFound.querySelector('.odoo-editor-editable') ? null : elementFound;
+    let element = node;
+    while (element && element.nodeType !== Node.ELEMENT_NODE) {
+        element = element.parentNode;
     }
-    return selector && element ? element.closest(selector) : element || node;
+    if (element && selector) {
+        element = element.closest(selector);
+    }
+    return element && element.querySelector('.odoo-editor-editable') ? null : element;
 }
 
 /**