Update duckdb index files

.gitattributes

@@ -13,3 +13,4 @@ mcd3/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mcd2/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mcd3/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 query_complexity_split/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+query_complexity_split/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

query_complexity_split/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:270237f7c2c8af7b236ab1c7e86a6bf11fe236606980bf12c32effd91d23fd71
+size 29634560