Revert "fix: add WebSocket keepalive pings to prevent idle disconnects (#646) (#925)"

This reverts commit 96e5b4b639.

proxy/raw_websocket.py

@@ -154,13 +154,6 @@ class RawWebSocket:
                 self._build_frame(self.OP_BINARY, part, mask=True))
         await self.writer.drain()
 
-    async def send_ping(self, payload: bytes = b''):
-        if self._closed:
-            raise ConnectionError("WebSocket closed")
-        frame = self._build_frame(self.OP_PING, payload, mask=True)
-        self.writer.write(frame)
-        await self.writer.drain()
-
     async def recv(self) -> Optional[bytes]:
         while not self._closed:
             opcode, payload = await self._read_frame()