null_count is omitted for large columns in parquet files

### Describe the bug, including details regarding any error messages, version, and platform.

Currently in [ParquetMetadataConverter.java](https://github.com/apache/parquet-java/blob/7be05b4702df78ae0c0c6b44adc6b7b7af2d931f/parquet-hadoop/src/main/java/org/apache/parquet/format/converter/ParquetMetadataConverter.java), there is a guard that prevents the writing of statistics such as min/max AND null_count when the stats are larger than the max allowed size under truncation. The rationale for this makes sense for omitting min/max, however null_count can be written on the file despite the size of its content. See the code below:

https://github.com/apache/parquet-java/blob/7be05b4702df78ae0c0c6b44adc6b7b7af2d931f/parquet-hadoop/src/main/java/org/apache/parquet/format/converter/ParquetMetadataConverter.java#L800-L807

The missing `null_count` metadata sometimes causes downstream consumers of the parquet files to error. For example in Snowflake we are seeing the following kind of error:

```
non-nullable column without default has null values according to file statistics
```

### Component(s)

Core

从 parquet-hadoop/src/main/java/org/apache/parquet/format/converter/ParquetMetadataConverter.java 中 800-807 行附近的 guard 开始。检查大小限制当前如何抑制统计信息，然后确保即使省略 min/max 也会保留 null_count；当包含大列的 Parquet 文件包含 null_count 元数据并避免报告的下游错误时，即表示完成。

由索引模型根据 Issue 内容生成。