Update duckdb index files

.gitattributes

@@ -248,3 +248,4 @@ 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/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+bengali/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

bengali/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:87e54278715367b6d327290556d0231af595dab3f6163602bb44b4b23638af21
+size 3944448