[v1.x] Backport #2257 and cut a release: the stateless Streamable HTTP client-disconnect fix (#2064) ships only in 2.0.0 pre-releases; latest stable v1.28.1 still carries the crashing send_log_message call

[v1.x] Backport #2257 and cut a release: the stateless Streamable HTTP client-disconnect fix (#2064) ships only in 2.0.0 pre-releases; latest stable v1.28.1 still carries the crashing send_log_message call #5101