Use default chunk size as 4 MB than than 16Mb in arrow's rolling policy

### Describe the enhancement requested

Apache Arrow currently calculates chunk sizes based on the assumption that Netty's PooledByteBufAllocatorL uses a 16MB page size. If size is blow 16MB, will use nextPowerOfTwo of requestSize.

```java
public long getRoundedSize(long requestSize) {
return requestSize < chunkSize ? CommonUtil.nextPowerOfTwo(requestSize) : requestSize;
}
```
However, Netty's default maximum buffer size has been reduced from 16MB to 4MB in recent versions (see https://github.com/netty/netty/pull/12108). This mismatch leads to memory inefficiency in scenarios where chunk sizes fall between 4MB and 16MB.

首先定位包含 getRoundedSize 和 chunkSize 默认值的 rolling policy 实现，然后查看 CommonUtil.nextPowerOfTwo 的使用方式。将该 policy 与 issue 中描述的 Netty 4 MB 默认值进行比较。当默认值使用 4 MB，并且相关测试（如果存在）覆盖了请求大小的现有行为时，即视为完成。

由索引模型根据 Issue 内容生成。