streamingccl: add even more LDR metrics to DB console

After #125320, a @dt @ajstorm wished for more metrics. We should add these when we have dev time or wish we had them during a debugging session:

Source side
- [ ] Row Updates Sent i.e. num kvs that went into batches that eventStream sent (single plot of sum across nodes)
- [ ] Megabytes Sent i.e. sum size of KVs that went out of eventStream (one plot per-node)
- [ ] Emission Queue Delay i.e. how long eventStream waits for Next() calls (two plots for p50+p99 per node)

Destination side
- [ ] Application Conflicts Placeholder / TODO.
- [ ] Application Failures / Updates send to DLQ Placeholder / TODO.
- [ ] Batches Applied ie. number of update/insert/delete queries run by the consumer (one plot per node)
- [ ] replanning events - i.e. the amount of times we had to replan the job

Jira issue: CRDB-39500

Start by reviewing issue #125320 and the streamingccl DB console work it introduced. Compare the source-side and destination-side metric checklist here, including the placeholder items, and consider the work done when the requested metrics are exposed in the console with the listed aggregation and per-node or percentile views.

Written by the indexing model from the issue text.