Update duckdb index files

.gitattributes

@@ -370,3 +370,4 @@ portuguese/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 spanish/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ukrainian/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 urdu/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+vietnamese/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

vietnamese/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9308e31233d700bc1fe65a83ffc2045145cd786d147e6914d14840f27aca798b
+size 334770176