Revert "remove swal hack"

This reverts commit 2d6b4f1216.

src/services/webPlatformUtils.service.ts

@@ -1,4 +1,5 @@
-import swal from 'sweetalert';
+import * as _swal from 'sweetalert';
+import { SweetAlert } from 'sweetalert/typings/core';
 
 import { DeviceType } from 'jslib/enums/deviceType';
 
@@ -7,6 +8,9 @@ import { PlatformUtilsService } from 'jslib/abstractions/platformUtils.service';
 
 import { Utils } from 'jslib/misc/utils';
 
+// Hack due to Angular 5.2 bug
+const swal: SweetAlert = _swal as any;
+
 export class WebPlatformUtilsService implements PlatformUtilsService {
     identityClientId: string = 'web';