[FIX] web_editor: prevent merging of unbreakable node

closes odoo/odoo#75432

X-original-commit: 1632bf17090b38eb8998edb09c1522929dc0312b
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

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

@@ -12,6 +12,7 @@ import {
     isFontAwesome,
     isMediaElement,
     getDeepRange,
+    isUnbreakable,
 } from './utils.js';
 
 const NOT_A_NUMBER = /[^\d]/g;
@@ -93,7 +94,7 @@ class Sanitize {
         }
 
         // Merge identical elements together
-        while (areSimilarElements(node, node.previousSibling)) {
+        while (areSimilarElements(node, node.previousSibling) && !isUnbreakable(node)) {
             getDeepRange(this.root, { select: true });
             const restoreCursor = preserveCursor(this.root.ownerDocument);
             const nodeP = node.previousSibling;