Without `query.live_analyze_metrics`, both the Flight stream and the
in-process region query path only snapshot execution metrics after each
produced record batch. A timed out EXPLAIN ANALYZE VERBOSE that is
stalled mid-scan therefore records only stale or empty remote (stage 1)
metrics in its slow query payload.
Enable live analyze metrics for `/v1/sql` requests so 1s-heartbeat
metric snapshots keep flowing; all consumers additionally gate on
`explain_verbose`, making this a no-op for other statements.
Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>