fix clippy warnings

Author: JanKaul

iceberg-rust/src/table/transaction/operation.rs

@@ -154,19 +154,15 @@ impl Operation {
                         .with_format_version(table_metadata.format_version)
                         .with_status(Status::Added)
                         .with_data_file(data_file)
-                        .build()
-                        .map_err(crate::spec::error::Error::from)
-                        .map_err(Error::from)
+                        .build().map_err(Error::from)
                 });
 
                 let new_deletefile_iter = delete_files.into_iter().map(|data_file| {
                     ManifestEntry::builder()
                         .with_format_version(table_metadata.format_version)
                         .with_status(Status::Added)
                         .with_data_file(data_file)
-                        .build()
-                        .map_err(crate::spec::error::Error::from)
-                        .map_err(Error::from)
+                        .build().map_err(Error::from)
                 });
 
                 let snapshot_id = generate_snapshot_id();