Remove erroneous assertion on operation state during ntcr::StreamSocket::privateSendRaw(ntsa::Data)

[mattrm456]

This PR removes an erroneous assertion:

BSLS_ASSERT((!error && context.bytesSent() > 0) || (error == ntsa::Error::e_WOULD_BLOCK));

in ntcr::StreamSocket::privateSendRaw() in the code path taken when trying to send and ntsa::Data. This assertion cannot be true if the send buffer is already full and we must enqueue the entirety of the ntsa::Data onto the write queue. This assertion appears to have been left-over from a prior implementation iteration and not cleaned up when the implementation evolved. This assertion does not appear in the more-commonly taken code path when the user is trying to send a bdlbb::Blob.