[IMP] web_editor: render templates insertion collaborative-friendly

In Knowledge, there is a custom `KnowledgeHtmlField` which adds a menu
placeholder if the `HtmlField` value is empty. It evaluates if it is empty after
each `historyStep`.

This commit introduces new collaborative step events so that the
`KnowledgeHtmlField` is able to properly hide/show that menu even after a
collaborator made the value empty.

task-3378266

X-original-commit: odoo/odoo@b6f103bd3e
Part-of: odoo/odoo#128962

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

@@ -1160,6 +1160,7 @@ export class OdooEditor extends EventTarget {
         this._handleCommandHint();
         this.multiselectionRefresh();
         this.observerActive();
+        this.dispatchEvent(new Event('historyResetFromSteps'));
     }
     historyGetMissingSteps({fromStepId, toStepId}) {
         const fromIndex = this._historySteps.findIndex(x => x.id === fromStepId);
@@ -1661,6 +1662,7 @@ export class OdooEditor extends EventTarget {
         this.historyResetLatestComputedSelection();
         this._handleCommandHint();
         this.multiselectionRefresh();
+        this.dispatchEvent(new Event('onExternalHistorySteps'));
     }
 
     // Multi selection