[FIX] web_editor: ensure no sibling tables for Firefox

Firefox doesn't seem to do well with sibling tables, so we need to
wrap them each in separate rows.

X-original-commit: 625a6545ee9e64a90e36b676c5b7b9a3c8d42418
Part-of: odoo/odoo#124465

addons/web_editor/static/src/js/backend/convert_inline.js

@@ -309,6 +309,16 @@ function bootstrapToTable(editable) {
     for (const table of editable.querySelectorAll('table')) {
         table.removeAttribute('o-temp-width');
     }
+    // Merge tables in tds into one common table, each in its own row.
+    const tds = [...editable.querySelectorAll('td')]
+        .filter(td => td.children.length > 1 && [...td.children].every(child => child.nodeName === 'TABLE'))
+        .reverse();
+    for (const td of tds) {
+        const table = _createTable();
+        const trs = [...td.children].map(child => _wrap(child, 'td')).map(wrappedChild => _wrap(wrappedChild, 'tr'));
+        trs[0].before(table);
+        table.append(...trs);
+    }
 }
 /**
  * Convert Bootstrap cards to table structures.