Fix intermittent failures when moving a freetext annotation in integration tests

When an editor is moved with the keyboard or in dragging it, it is moved in the DOM in order
to make screen readers happy. But this move is slightly postponed thanks to a setTimeout(..., 0).
The failures were very likely due to the fact that intermittently the DOM move was done in
the middle of the next key sequence which was making the move on screen failing.

src/display/editor/editor.js

@@ -1278,6 +1278,11 @@ class AnnotationEditor {
     this.#moveInDOMTimeout = setTimeout(() => {
       this.#moveInDOMTimeout = null;
       this.parent?.moveEditorInDOM(this);
+      if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("TESTING")) {
+        this._uiManager._eventBus.dispatch("editormovedindom", {
+          source: this,
+        });
+      }
     }, 0);
   }