Ignore EPIPE when sending NewSessionTickets in TLSv1.3

If a client sends data to a server and then immediately closes without
waiting to read the NewSessionTickets then the server can receive EPIPE
when trying to write the tickets and never gets the opportunity to read
the data that was sent. Therefore we ignore EPIPE when writing out the
tickets in TLSv1.3

Fixes #6904

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6944)