Delete old duckdb index files

default/partial-test/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:fcaa0d406c3e0ac6eed1560ecf505625ce86b6a95f7485f8d718c2ff8bf4f72a
-size 1685336064

default/partial-train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:c3720e0d7351ab150ec56662e6f5487475dd5d8dd022a2f7338cbc212a277fc3
-size 8065134592

default/partial-validation/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:8310f0b441e4b381b8a3a4a6d42b3c2f90b2f72794b6710d5c688d626ea5871e
-size 1686908928