Update duckdb index files

.gitattributes

@@ -340,3 +340,4 @@ telugu/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 telugu/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 thai/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 thai/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+thai/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

thai/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:bf38ebaff9bf8e168ec604841833fe2738565a91e1bde601bdb3a863aaa58ef0
+size 3682304