Update duckdb index files

.gitattributes

@@ -191,3 +191,4 @@ mbpp_structured/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mbpp_structured/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 multiarith/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 multiarith/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+multiarith/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

multiarith/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c88c05b2fd20e232085a0e179ac838a12abd6bc1da9cb78512ac36b706795653
+size 1060864