Fix error that erased app content when update.

Author: Thomasr

server/api-service/lowcoder-domain/src/main/java/org/lowcoder/domain/application/service/ApplicationServiceImpl.java

@@ -349,10 +349,10 @@ public Flux<Application> findAll() {
 
     @Override
     public Mono<Boolean> updateLastEditedAt(String applicationId, Instant time, String visitorId) {
-        return repository.findById(applicationId)
+        return repository.findByIdIn(List.of(applicationId))
                 .filter(application -> application.getEditingUserId().equals(visitorId))
                 .doOnNext(application -> application.setLastEditedAt(time))
                 .flatMap(repository::save)
-                .hasElement();
+                .hasElements();
     }
 }