fix: export FromArrowSchema for the bundle library

The Parquet reader in libiceberg_bundle now calls FromArrowSchema, which
lives in libiceberg, so shared builds failed to link it. Mark it
ICEBERG_EXPORT like ToArrowSchema.

Signed-off-by: Vincent <1729065730@qq.com>

Author: ump45nose

src/iceberg/schema_internal.h

@@ -45,8 +45,8 @@ ICEBERG_EXPORT Status ToArrowSchema(const Schema& schema, ArrowSchema* out);
 /// \param[in] schema The Arrow schema to convert.
 /// \param[in] schema_id The schema ID of the Iceberg schema.
 /// \return The Iceberg schema or an error if the conversion fails.
-Result<std::unique_ptr<Schema>> FromArrowSchema(const ArrowSchema& schema,
-                                                std::optional<int32_t> schema_id);
+ICEBERG_EXPORT Result<std::unique_ptr<Schema>> FromArrowSchema(
+    const ArrowSchema& schema, std::optional<int32_t> schema_id);
 
 /// \brief Convert a struct type to an Iceberg schema.
 ///