The page compressedSize printed by the ShowPagesCommand is actually uncompressedSize

It seems that the data page obtained by calling PageReader.readPage() (L122 in ShowPagesCommand) is decompressed, and the bytes obtained by DataPageV1 is decompressed.

**Reporter**: [Yujiang Zhong](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=zhongyuj) / @zhongyujiang
#### Original Issue Attachments:
- [59fa778d-d870-49f2-87f7-046e2e87ef9f.jpeg](https://issues.apache.org/jira/secure/attachment/13066545/59fa778d-d870-49f2-87f7-046e2e87ef9f.jpeg)
- [image-2024-02-07-16-48-08-016.png](https://issues.apache.org/jira/secure/attachment/13066544/image-2024-02-07-16-48-08-016.png)

_{**Note**: *This issue was originally created as [PARQUET-2427](https://issues.apache.org/jira/browse/PARQUET-2427). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start in ShowPagesCommand at the PageReader.readPage() call noted in the issue, then trace how DataPageV1 exposes its bytes and how compressedSize is printed. Reproduce the command's page-size output and confirm that the displayed value represents decompressed data; done means the reported compressed size matches the compressed page data.

Written by the indexing model from the issue text.