Delete old duckdb index files

default/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:f832b4daea5c3fc0998d0f5fbcda89457d509a4130a5b3c4aed3cd685c50e47b
-size 186658816

wenge-research--yayi_domain_subset/train/index.duckdb

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:dd293514180dabc4a58c1d592926545882966efd1922118d5d4ad03931cf1d73
-size 185610240