Encode audio as HF Audio feature (was raw binary) so the dataset loads remotely (verify-pr/board)

data/test-00000-of-00003.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6e77a127ef06a84f4b066a5eab926d4af2cc2b856d74466b3552d4b547b17aba
-size 495029306
+oid sha256:3b2db53b6b661542633e7e22991660c0b0ee2308b97f15bb1952abfcf0391fd5
+size 495953448

data/test-00001-of-00003.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3b6be14ccf96de11849993cf1132e5f1a9e7a18b31c883587cf35fb21d02936b
-size 502580809
+oid sha256:825adb67adc6e15fb6752ca7c33b9f512e2cfbfe4af84ee64857a7c5d60f9792
+size 503462947

data/test-00002-of-00003.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:c0fc5813f5c437db58decda0aa0295b7847c20a2de28eacef5f869ec16165e7a
-size 497663463
+oid sha256:c4edb1f59052de39b3a394df73d47f073672f95a6ef28e0a957cd93a71d6fae2
+size 499285315