Update duckdb index files

.gitattributes

@@ -246,3 +246,4 @@ arabic/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 azerbaijani/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 azerbaijani/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 azerbaijani/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+bengali/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

bengali/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5d80a337200c6b0446ddb3d636c815bcfdb16a93c3294ff7d8760c1fb0f093b9
+size 26226688