Update middleware test

Assert that `isAnonymous` is set for `SignedInUser`
authenticated via API key.

pkg/middleware/middleware_test.go

@@ -187,6 +187,8 @@ func TestMiddlewareContext(t *testing.T) {
 
 			Convey("Should init middleware context", func() {
 				So(sc.context.IsSignedIn, ShouldEqual, true)
+				So(sc.context.SignedInUser, ShouldNotBeNil)
+				So(sc.context.SignedInUser.IsAnonymous, ShouldEqual, true)
 				So(sc.context.OrgId, ShouldEqual, 12)
 				So(sc.context.OrgRole, ShouldEqual, models.ROLE_EDITOR)
 			})