Add sw_tz_znz: 17.8h Zanzibari Swahili from tz_sw_znz

data/sw_tz_znz/test-00000.parquet

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+size 26156030

data/sw_tz_znz/train-00000.parquet

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+version https://git-lfs.github.com/spec/v1
+oid sha256:5a50eda821aa344240ef110946f65974d59d794e1e521ebcc9f0e21524193a11
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