Update duckdb index files

.gitattributes

@@ -57,3 +57,4 @@ Patt--MultiRC_TH/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 Patt--MultiRC_TH/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 default/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 default/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+default/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

default/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e36d58bd25277e32437a86dd1d06fa98fc6027b8b57c7584a5a2cc82906acba0
+size 20721664