Delete old duckdb index files

default/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:3f6bf7a9a9f69000b5b143beefe1cf0bbc6ffe6158be46d155dfbafd59f5de92
-size 4052234240

default/train/partial-index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:9a4ac84912c5cf85e0176d9e6c37ed0d9751b7e673ef9f12077ad815ccb3f15d
-size 4402720768