writeToStreamDataBlock() waited for the rest of a body for as long as
connected() held. A server that stops sending part way through a body
without closing the connection leaves connected() true, so getString()
never returned and the unit stopped responding. Give up after
_tcpTimeout without data and return HTTPC_ERROR_READ_TIMEOUT, as
handleHeaderResponse() already does. Same fix as arendst/Tasmota#25139.
Adam Matthews