Fix directory traversal vulnerability in tar unpack

Iterate over tar archive entries and call `unpack_in` on each entry instead
of using the top-level `Archive::unpack` method, ensuring proper directory
traversal protections are applied.

Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com>

Author: google-labs-jules[bot]

stdlib/src/compress.rs

@@ -258,7 +258,10 @@ pub fn untar_archive(archive_path: &str, dest_dir: &str) -> std::io::Result<()>
     // from escaping the destination directory. Therefore, we revert the manual
     // path validation that caused a regression with uncanonicalized relative paths.
 
-    a.unpack(dest_dir)?;
+    for entry in a.entries()? {
+        let mut entry = entry?;
+        entry.unpack_in(dest_dir)?;
+    }
     Ok(())
 }