Delete sw_tz_znz orphan config (empty transcripts; data lives correctly in sw_tz/tz_sw_znz-*)

data/sw_tz_znz/test-00000.parquet

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:d98a74ca6ef0e0966989954b5222cc1dee3b9b9885736d5f62cd49b055f12101
-size 26156030

data/sw_tz_znz/train-00000.parquet

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:5a50eda821aa344240ef110946f65974d59d794e1e521ebcc9f0e21524193a11
-size 517312652