Stop blackhole detection when a duplicate ACK causes packets to be detected lost. Protected by existing gfe2_reloadable_flag_quic_default_enable_5rto_blackhole_detection2. Do not close connection when blackhole is detected but there is no in flight packets. PiperOrigin-RevId: 326693232 Change-Id: Id75b01e399fad12dcfc12dabd7245a2f059663de