Merge pull request #31166 from themindoverall/hapi/route-pre-assign-optional

[hapi] Make RouteOptionsPreObject.assign optional

types/hapi/index.d.ts

@@ -1428,7 +1428,7 @@ export interface RouteOptionsPreObject {
     /**
      * key name used to assign the response of the method to in request.pre and request.preResponses.
      */
-    assign: string;
+    assign?: string;
     /**
      * A failAction value which determine what to do when a pre-handler method throws an error. If assign is specified and the failAction setting is not 'error', the error will be assigned.
      */