Remove untranscribed Paiwan example audio

Paiwan_4557 has audio and a Chinese translation but no source-language text in the ILRDF API, so it is no longer published in FormosanBank XML.

Paiwan/Paiwan/Paiwan_4557.mp3

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:bc18484cc7255e516beb3cd637b369719d1ba6712c06638b01cb652febf2d839
-size 187406