Update duckdb index files

.gitattributes

@@ -56,3 +56,4 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 default/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 inflated/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 raw/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+flattened/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text

flattened/partial-train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:fba32928b0208d523d7992115fcf3d67e3325b3c0f3e579cfe701d97d2163f89
+size 3909890048