fix(hints_sending_in_progress): is failing with "No results from Prometheus"
fix(hints_sending_in_progress): is failing with "No results from Prometheus"

Seem like the scrape_interval was set to 20s in:
scylladb/scylla-monitoring@6acafea

Since our query was with 15s, it returned without data we should make our
range a bit bigger then the step (we are using scrape_interval for the step)
in the api call

Fixes: #2123

scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests