Delete old duckdb index files

default/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:fac529f136143ec7b23282be386d113d73d41c4e01d9b2322f3008b1f1d568ef
-size 4029165568

default/train/partial-index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:68f2ab1585bbf593715ba648aa24c51fdd7178e4f5bf05e258908249638d829a
-size 4486868992