fix(upgrade-on-K8S): perform proper check for scylla version
fix(upgrade-on-K8S): perform proper check for scylla version

'get_scylla_version()' method of a "scylla node" started returning
detailed scylla version [1] and upgrade test started failing on K8S
backends.
Fix it by making proper version check there.

[1] https://github.com/scylladb/scylla-cluster-tests/commit/7bdb0e60

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,scylladb/scylla-longevity-tests