fix(upgrade): increase load time during upgrade/rollback
fix(upgrade): increase load time during upgrade/rollback

Increase load time during upgrade/rollback for rolling upgrade SLA test

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