[Not consistent with official documentation]listBulkInsertTasks() CollectionName NULL check

[fall-nebula]

In official documentation said List all tasks Parameter [collection_name ] is optional. And said "Leave the value empty if you want to list all tasks recorded by Milvus root coords".
Docs
But in io.milvus.client.AbstractMilvusGrpcClient#listBulkInsertTasks used:

            ListImportTasksRequest listImportTasksRequest = ListImportTasksRequest.newBuilder()
                    .setCollectionName(requestParam.getCollectionName())
                    .setLimit(requestParam.getLimit())
                    .build();

And io.milvus.grpc.ListImportTasksRequest.Builder#setCollectionName don't allow value is null.

    public ListImportTasksRequest.Builder setCollectionName(
            java.lang.String value) {
        if (value == null) {
            throw new NullPointerException();
        }

        collectionName_ = value;
        onChanged();
        return this;
    }

[yhmo]

Fixed by this pr, which will be released in v2.2.9