Fix creatorUserId is required error when opening sticker picker (#10423)

* Use sender if sticker picker widget does not have creatorUserId

* Add creatorUserId when creating sticker picker widgets

* Add e2e test for stickerpicker widget missing creatorUserId

* Fix stickerpicker widget event data in e2e tests

* Fix userId in stickerpicker e2e tests

* Fix linter errors

src/components/views/rooms/Stickerpicker.tsx

@@ -273,7 +273,7 @@ export default class Stickerpicker extends React.PureComponent<IProps, IState> {
                 roomId: stickerpickerWidget.content.roomId,
                 eventId: stickerpickerWidget.content.eventId,
                 avatar_url: stickerpickerWidget.content.avatar_url,
-                creatorUserId: stickerpickerWidget.content.creatorUserId,
+                creatorUserId: stickerpickerWidget.content.creatorUserId || stickerpickerWidget.sender,
             };
 
             stickersContent = (

src/utils/WidgetUtils.ts

@@ -236,13 +236,6 @@ export default class WidgetUtils {
         widgetName: string,
         widgetData: IWidgetData,
     ): Promise<void> {
-        const content = {
-            type: widgetType.preferred,
-            url: widgetUrl,
-            name: widgetName,
-            data: widgetData,
-        };
-
         const client = MatrixClientPeg.get();
         // Get the current widgets and clone them before we modify them, otherwise
         // we'll modify the content of the old event.
@@ -257,11 +250,21 @@ export default class WidgetUtils {
 
         const addingWidget = Boolean(widgetUrl);
 
+        const userId = client.getSafeUserId();
+
+        const content = {
+            type: widgetType.preferred,
+            url: widgetUrl,
+            name: widgetName,
+            data: widgetData,
+            creatorUserId: userId,
+        };
+
         // Add new widget / update
         if (addingWidget) {
             userWidgets[widgetId] = {
                 content: content,
-                sender: client.getUserId()!,
+                sender: userId,
                 state_key: widgetId,
                 type: "m.widget",
                 id: widgetId,