enhance: binlog record writer return list of field binlogs rather than map

[shaoting-huang]

type BinlogRecordWriter interface {
	RecordWriter
	GetLogs() (
		fieldBinlogs map[FieldID]*datapb.FieldBinlog,
		statsLog *datapb.FieldBinlog,
		bm25StatsLog map[FieldID]*datapb.FieldBinlog,
	)
	GetRowNum() int64
	FlushChunk() error
	GetBufferUncompressed() uint64
	Schema() *schemapb.CollectionSchema
}

It is better to return list of fieldBinlogs rather than map[fieldId][binlogs] and use sort field binlogs by field id outside.