Use WidgetType more often to avoid breaking new sticker pickers

Turns out that setUserWidget() wasn't updated to take a real WidgetType, but the code in ScalarMessaging thought it did. This leads to integration managers trying to add sticker widgets with an object `type` rather than a string `type`, which doesn't work.

This updates other code paths which call into the various widget classes to use WidgetType more often. The actual code path for fixing widgets is resolved in WidgetUtils for the setUserWidget function body.

src/ScalarAuthClient.js

@@ -23,6 +23,7 @@ import request from "browser-request";
 
 import * as Matrix from 'matrix-js-sdk';
 import SdkConfig from "./SdkConfig";
+import {WidgetType} from "./widgets/WidgetType";
 
 // The version of the integration manager API we're intending to work with
 const imApiVersion = "1.1";
@@ -233,20 +234,20 @@ export default class ScalarAuthClient {
      * Mark all assets associated with the specified widget as "disabled" in the
      * integration manager database.
      * This can be useful to temporarily prevent purchased assets from being displayed.
-     * @param  {string} widgetType [description]
-     * @param  {string} widgetId   [description]
+     * @param  {WidgetType} widgetType The Widget Type to disable assets for
+     * @param  {string} widgetId   The widget ID to disable assets for
      * @return {Promise}           Resolves on completion
      */
-    disableWidgetAssets(widgetType, widgetId) {
+    disableWidgetAssets(widgetType: WidgetType, widgetId) {
         let url = this.apiUrl + '/widgets/set_assets_state';
         url = this.getStarterLink(url);
         return new Promise((resolve, reject) => {
             request({
-                method: 'GET',
+                method: 'GET', // XXX: Actions shouldn't be GET requests
                 uri: url,
                 json: true,
                 qs: {
-                    'widget_type': widgetType,
+                    'widget_type': widgetType.preferred,
                     'widget_id': widgetId,
                     'state': 'disable',
                 },