kv/concurrency: increase kv.lock_table.coordinator_liveness_push_delay to 50ms

[jseldess]

Jesse Seldess (jseldess) commented:

PR: cockroachdb/cockroach#50161

From release notes:

Transaction liveness pushes are now delayed by 50ms, up from 10ms. This allows high contention workloads to sustain high throughput up to much larger concurrency levels. [#50161][#50161] {% comment %}doc{% endcomment %}

Jira Issue: DOC-612