"Select Contet Pack" stuck in "loading..."

**Environment:**
OS: Debian 9 stretch
Graylog ver: 2.5.1
Mongdb ver: 3.6.10
Elasticsearch ver: 6.2.4
Browser: any

**Description:**
In tab "Content packs" within graylog, it stucks in "loading".
To reproduce: click on "Content packs" and "loading" never desappears.

**Testcase:**
Checking server.log from graylog:
```2019-02-08T14:16:06.844+01:00 ERROR [AnyExceptionClassMapper] Unhandled exception in REST resource
java.lang.RuntimeException: IOException encountered while reading from a byte array input stream
at org.mongojack.internal.stream.JacksonDBDecoder.decode(JacksonDBDecoder.java:67) ~[graylog.jar:?]
at com.mongodb.DBDecoderAdapter.decode(DBDecoderAdapter.java:49) ~[graylog.jar:?]
at com.mongodb.DBDecoderAdapter.decode(DBDecoderAdapter.java:29) ~[graylog.jar:?]
at com.mongodb.operation.CommandResultArrayCodec.decode(CommandResultArrayCodec.java:52) ~[graylog.jar:?]
at com.mongodb.operation.CommandResultDocumentCodec.readValue(CommandResultDocumentCodec.java:60) ~[graylog.jar:?]
at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:84) ~[graylog.jar:?]
at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:41) ~[graylog.jar:?]
at org.bson.codecs.configuration.LazyCodec.decode(LazyCodec.java:47) ~[graylog.jar:?]
at org.bson.codecs.BsonDocumentCodec.readValue(BsonDocumentCodec.java:101) ~[graylog.jar:?]
at com.mongodb.operation.CommandResultDocumentCodec.readValue(CommandResultDocumentCodec.java:63) ~[graylog.jar:?]
at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:84) ~[graylog.jar:?]
at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:41) ~[graylog.jar:?]
at com.mongodb.connection.ReplyMessage.(ReplyMessage.java:50) ~[graylog.jar:?]
at com.mongodb.connection.CommandProtocol.getResponseDocument(CommandProtocol.java:132) ~[graylog.jar:?]
at com.mongodb.connection.CommandProtocol.execute(CommandProtocol.java:111) ~[graylog.jar:?]
at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:159) ~[graylog.jar:?]
at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:289) ~[graylog.jar:?]
at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:176) ~[graylog.jar:?]
at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:216) ~[graylog.jar:?]
at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:207) ~[graylog.jar:?]
at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:113) ~[graylog.jar:?]
at com.mongodb.operation.FindOperation$1.call(FindOperation.java:715) ~[graylog.jar:?]
at com.mongodb.operation.FindOperation$1.call(FindOperation.java:709) ~[graylog.jar:?]
at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:433) ~[graylog.jar:?]
at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:406) ~[graylog.jar:?]
at com.mongodb.operation.FindOperation.execute(FindOperation.java:709) ~[graylog.jar:?]
at com.mongodb.operation.FindOperation.execute(FindOperation.java:81) ~[graylog.jar:?]
at com.mongodb.Mongo.execute(Mongo.java:810) ~[graylog.jar:?]
at com.mongodb.Mongo$2.execute(Mongo.java:797) ~[graylog.jar:?]
at com.mongodb.DBCursor.initializeCursor(DBCursor.java:871) ~[graylog.jar:?]
at com.mongodb.DBCursor.hasNext(DBCursor.java:142) ~[graylog.jar:?]
at org.mongojack.DBCursor.hasNext(DBCursor.java:330) ~[graylog.jar:?]
at org.graylog2.bundles.BundleService.loadAll(BundleService.java:83) ~[graylog.jar:?]
at org.graylog2.rest.resources.system.bundles.BundleResource.listBundles(BundleResource.java:100) ~[graylog.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_191]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_191]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_191]
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:205) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347) ~[graylog.jar:?]
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102) ~[graylog.jar:?]
at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:326) [graylog.jar:?]
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271) [graylog.jar:?]
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267) [graylog.jar:?]
at org.glassfish.jersey.internal.Errors.process(Errors.java:315) [graylog.jar:?]
at org.glassfish.jersey.internal.Errors.process(Errors.java:297) [graylog.jar:?]
at org.glassfish.jersey.internal.Errors.process(Errors.java:267) [graylog.jar:?]
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317) [graylog.jar:?]
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:305) [graylog.jar:?]
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1154) [graylog.jar:?]
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:384) [graylog.jar:?]
at org.glassfish.grizzly.http.server.HttpHandler$1.run(HttpHandler.java:224) [graylog.jar:?]
at com.codahale.metrics.InstrumentedExecutorService$InstrumentedRunnable.run(InstrumentedExecutorService.java:176) [graylog.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_191]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_191]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_191]
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "id" (class org.graylog2.bundles.ConfigurationBundle), not marked as ignorable (12 known properties: "outputs", "streams", "lookup_data_adapters", "lookup_caches", "inputs", "lookup_tables", "name", "description", "category", "dashboards", "grok_patterns", "_id"])
at [Source: de.undercouch.bson4jackson.io.LittleEndianInputStream@2d488ed; pos: 62] (through reference chain: org.graylog2.bundles.ConfigurationBundle["id"])
at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:62) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:834) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1093) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1478) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1456) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:282) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:3786) ~[graylog.jar:?]
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2181) ~[graylog.jar:?]
at org.mongojack.internal.stream.JacksonDBDecoder.decode(JacksonDBDecoder.java:77) ~[graylog.jar:?]
at org.mongojack.internal.stream.JacksonDBDecoder.decode(JacksonDBDecoder.java:64) ~[graylog.jar:?]```