Delete old duckdb index files

curated/test/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:9f20656967dd2458b8b4efa3ef57d68d16795d3866f9693668a5050d23bbdeb2
-size 1060864

curated/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:eb81c0b5d77f732c1ae143439413641b515b6dc6de8346b6d05239d918f5b1c3
-size 1323008

mined/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:d485c01607a8bfbee518c7f16d2cfd4f9a9e641dc5d3fd00e286f58e039550d5
-size 135540736