feat: support different types for CompatReader (#3745)

* feat: support different types for `CompatReader`

* chore: only compare whether we need: (data_type)

* fix: optimize code based on review suggestions

- add unit test `test_safe_cast_to_null` to test safely cast
- add DataType to projected_fields
- remove TODO

* fix: assert_eq fail on `projection.rs`

* style: codefmt

* style: fix the code based on review suggestions

src/store-api/src/metadata.rs

@@ -107,6 +107,10 @@ impl ColumnMetadata {
     pub fn decode_list(bytes: &[u8]) -> serde_json::Result<Vec<Self>> {
         serde_json::from_slice(bytes)
     }
+
+    pub fn is_same_datatype(&self, other: &Self) -> bool {
+        self.column_schema.data_type == other.column_schema.data_type
+    }
 }
 
 #[cfg_attr(doc, aquamarine::aquamarine)]