build: Fix nanoarrow download URL failure in CI

The build was failing in CI because `https://dlcdn.apache.org/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz` returned a 404 error. This suggests the artifact has been removed from the mirror network (likely moved to archive).

This commit updates `cmake_modules/IcebergThirdpartyToolchain.cmake` to include fallback URLs for `nanoarrow`:
1.  The Apache dynamic download link (`dyn/closer.lua`).
2.  The original `dlcdn` link (kept as one of the options).
3.  The `archive.apache.org` link (stable location for older releases).
4.  The GitHub release artifact link.

This ensures the build can proceed even if the primary mirror is missing the file.

Co-authored-by: wgtmac <4684607+wgtmac@users.noreply.github.com>

Author: google-labs-jules[bot]

cmake_modules/IcebergThirdpartyToolchain.cmake

@@ -260,7 +260,10 @@ function(resolve_nanoarrow_dependency)
     set(NANOARROW_URL "$ENV{ICEBERG_NANOARROW_URL}")
   else()
     set(NANOARROW_URL
+        "https://www.apache.org/dyn/closer.lua?action=download&filename=/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
         "https://dlcdn.apache.org/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
+        "https://archive.apache.org/dist/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
+        "https://github.com/apache/arrow-nanoarrow/releases/download/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
     )
   endif()