fix: remove duplicate code left by main-merge auto-resolution

The merge of main into pr-b-cleanup-hardening auto-resolved by keeping
both the new and old versions side-by-side in three places:

  * transaction.cc: duplicate Result<const TableMetadata*>
    finalize_result definition (compile error: redefinition).
  * expire_snapshots.cc: duplicate #include <string>.
  * expire_snapshots.cc: an old DeleteFile/DeleteFiles pair (the
    pre-hardening serial loop with the original "TODO add retry"
    comment) was kept inside the new DeleteFiles body, leaving an
    unmatched brace and two redefined methods.

Drop the duplicates so the file compiles and matches the intended
post-merge state. clang-format remains clean and all ExpireSnapshots
tests pass.

Author: shangxinli

src/iceberg/transaction.cc

@@ -368,11 +368,6 @@ Result<std::shared_ptr<Table>> Transaction::Commit() {
           ? Result<const TableMetadata*>(commit_result.value()->metadata().get())
           : std::unexpected(commit_result.error());
 
-  Result<const TableMetadata*> finalize_result =
-      commit_result.has_value()
-          ? Result<const TableMetadata*>(commit_result.value()->metadata().get())
-          : std::unexpected(commit_result.error());
-
   for (const auto& update : pending_updates_) {
     std::ignore = update->Finalize(finalize_result);
   }

src/iceberg/update/expire_snapshots.cc

@@ -29,7 +29,6 @@
 #include <span>
 #include <string>
 #include <thread>
-#include <string>
 #include <unordered_set>
 #include <vector>
 
@@ -185,24 +184,6 @@ class FileCleanupStrategy {
     std::vector<std::string> as_vec(paths.begin(), paths.end());
     RunInParallel<std::string>(std::span<const std::string>(as_vec),
                                [this](const std::string& p) { DeleteFile(p); });
-  /// \brief Delete a single file
-  void DeleteFile(const std::string& path) {
-    try {
-      if (delete_func_) {
-        delete_func_(path);
-      } else {
-        std::ignore = file_io_->DeleteFile(path);
-      }
-    } catch (...) {
-      /// TODO(shangxinli): add retry
-    }
-  }
-
-  /// TODO(shangxinli): Add bulk deletion
-  void DeleteFiles(const std::unordered_set<std::string>& paths) {
-    for (const auto& path : paths) {
-      DeleteFile(path);
-    }
   }
 
   bool HasAnyStatisticsFiles(const TableMetadata& metadata) const {