[avro] Do not flush on every block for DataFileWriter (apache#3893)

paimon-format/src/main/java/org/apache/paimon/format/avro/AvroFileFormat.java

@@ -124,6 +124,7 @@ private RowAvroWriterFactory(RowType rowType) {
                                         new DataFileWriter<>(datumWriter);
                                 dataFileWriter.setCodec(createCodecFactory(compression));
                                 dataFileWriter.create(schema, out);
+                                dataFileWriter.setFlushOnEveryBlock(false);
                                 return dataFileWriter;
                             });
         }