feat(screenshare) - add web security fix for electron (#13096)

use send the share screen sources using the external api

---------

Co-authored-by: Gabriel Borlea <gabriel.borlea@8x8.com>

modules/API/external/external_api.js

@@ -91,7 +91,8 @@ const commands = {
     toggleTileView: 'toggle-tile-view',
     toggleVirtualBackgroundDialog: 'toggle-virtual-background',
     toggleVideo: 'toggle-video',
-    toggleWhiteboard: 'toggle-whiteboard'
+    toggleWhiteboard: 'toggle-whiteboard',
+    _requestDesktopSourcesResult: '_request-desktop-sources-result'
 };
 
 /**
@@ -159,7 +160,8 @@ const events = {
     'suspend-detected': 'suspendDetected',
     'tile-view-changed': 'tileViewChanged',
     'toolbar-button-clicked': 'toolbarButtonClicked',
-    'whiteboard-status-changed': 'whiteboardStatusChanged'
+    'whiteboard-status-changed': 'whiteboardStatusChanged',
+    '_request-desktop-sources': '_requestDesktopSources'
 };
 
 /**
@@ -1311,6 +1313,17 @@ export default class JitsiMeetExternalAPI extends EventEmitter {
         }
     }
 
+    /**
+     * Send request to request desktop sources.
+     *
+     * @returns {Promise} - Result.
+     */
+    _requestDesktopSources() {
+        return this._transport.sendRequest({
+            name: '_request-desktop-sources'
+        });
+    }
+
     /**
      * Passes an event along to the local conference participant to establish
      * or update a direct peer connection. This is currently used for developing