Expose `SignalService` to style guide

ts/styleguide/StyleGuideUtil.ts

@@ -21,6 +21,7 @@ import * as HTML from '../html';
 
 import * as Attachment from '../../ts/types/Attachment';
 import * as MIME from '../../ts/types/MIME';
+import { signalservice as SignalService } from '../../ts/protobuf/SignalService';
 
 // TypeScript wants two things when you import:
 //   1) a normal typescript file
@@ -131,6 +132,7 @@ parent.Signal.Components = {
   Quote,
 };
 parent.Signal.Util = Util;
+parent.SignalService = SignalService;
 parent.filesize = filesize;
 
 parent.ConversationController._initialFetchComplete = true;