Update duckdb index files

.gitattributes

@@ -355,3 +355,4 @@ uzbek/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 uzbek/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 uzbek/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 vietnamese/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+vietnamese/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

vietnamese/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:d13d7402facac758a7e6d5c33a8add8588b8f19da9c57d24b84a720f6e32a1ff
+size 31993856