fix: revert arrow converters

Author: dantengsky

src/query/expression/src/converts/arrow/from.rs

@@ -127,10 +127,7 @@ impl TryFrom<&Field> for TableField {
                 ArrowDataType::Decimal128(precision, scale) if *scale >= 0 => {
                     let size = DecimalSize::new(*precision, *scale as _)?;
                     match size.data_kind() {
-                        DecimalDataKind::Decimal64 => {
-                            TableDataType::Decimal(DecimalDataType::Decimal64(size))
-                        }
-                        DecimalDataKind::Decimal128 => {
+                        DecimalDataKind::Decimal64 | DecimalDataKind::Decimal128 => {
                             TableDataType::Decimal(DecimalDataType::Decimal128(size))
                         }
                         _ => unreachable!(),

src/query/expression/src/converts/arrow/to.rs

@@ -114,7 +114,6 @@ impl From<&TableField> for Field {
             TableDataType::Number(ty) => with_number_type!(|TYPE| match ty {
                 NumberDataType::TYPE => ArrowDataType::TYPE,
             }),
-            // TODO Map DecimalDataType::Decimal64 to ArrowDataType::Decimal64?
             TableDataType::Decimal(
                 DecimalDataType::Decimal64(size) | DecimalDataType::Decimal128(size),
             ) => ArrowDataType::Decimal128(size.precision(), size.scale() as i8),