Delete old duckdb index files

default/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:efeef009d59054f6fd782817b3851f8715a8500cc42cecb5f361b728725f20a7
-size 6315585536

default/train/partial-index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:36b6b7f3163101370929d141d06d21de5ab2ac4779cdef2bf4deebe037d61802
-size 5495336960