Make DFSchema::datatype_is_semantically_equal public (#13429)

Author: Sevenannn

datafusion/common/src/dfschema.rs

@@ -686,7 +686,7 @@ impl DFSchema {
     /// name and type), ignoring both metadata and nullability.
     ///
     /// request to upstream: <https://github.com/apache/arrow-rs/issues/3199>
-    fn datatype_is_semantically_equal(dt1: &DataType, dt2: &DataType) -> bool {
+    pub fn datatype_is_semantically_equal(dt1: &DataType, dt2: &DataType) -> bool {
         // check nested fields
         match (dt1, dt2) {
             (DataType::Dictionary(k1, v1), DataType::Dictionary(k2, v2)) => {