toParquetMetadata method in ParquetMetadataConverter does not set dictionary page offset bit

toParquetMetadata method converts org.apache.parquet.hadoop.metadata.ParquetMetadata to org.apache.parquet.format.FileMetaData but this does not set the dictionary page offset bit in FileMetaData.

When a FileMetaData object is serialized while writing to the footer and then deserialized, the dictionary offset is lost as the dictionary page offset bit was never set.

PARQUET-1850  tried to fix this but it did only a partial fix.

It sets setDictionary_page_offset only if getEncodingStats are present
```java

if (columnMetaData.getEncodingStats() != null
&& columnMetaData.getEncodingStats().hasDictionaryPages())
{ metaData.setDictionary_page_offset(columnMetaData.getDictionaryPageOffset()); }
```
However, it should setDictionary_page_offset even when getEncodingStats are not present but encodings are present.

It should use the implementation in ColumnChunkMetatdata below:
```java

public boolean hasDictionaryPage() {
EncodingStats stats = getEncodingStats();
if (stats != null) {
return stats.hasDictionaryPages() && stats.hasDictionaryEncodedPages();
}

Set encodings = getEncodings();
return (encodings.contains(PLAIN_DICTIONARY) || encodings.contains(RLE_DICTIONARY));
}
```
So new change in ParquetMetadataCOnvertor should be like:

 
```java

if (columnMetaData.hasDictionaryPage()) { metaData.setDictionary_page_offset(columnMetaData.getDictionaryPageOffset()); }
```

**Reporter**: [Abhishek Dixit](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=abhishekd0907)
#### PRs and other links:
- [GitHub Pull Request #1340](https://github.com/apache/parquet-mr/pull/1340)

_{**Note**: *This issue was originally created as [PARQUET-2464](https://issues.apache.org/jira/browse/PARQUET-2464). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Inizia da ParquetMetadataConverter.toParquetMetadata e confronta la sua condizione per le pagine del dizionario con ColumnChunkMetadata.hasDictionaryPage(), come descritto nell’issue. Verifica che la serializzazione e la deserializzazione del footer preservino l’offset della pagina del dizionario quando le statistiche di encoding sono assenti ma sono presenti gli encoding del dizionario; controlla Pull Request #1340 per verificare il lavoro già esistente.

Scritto dal modello di indicizzazione a partire dal testo della issue.