fix(grafana_snapshot): Scrolldown grafana page before create live snapshot
fix(grafana_snapshot): Scrolldown grafana page before create live snapshot

During getting live grafana snapshot, if page is not scrolled down,
panels which not on page will don't have data on live snapshot.
if scroll page and wait data load, livesnapshot contains valid data
on panels.

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