gms/endpoint_state: mark methods using get_status noexcept
gms/endpoint_state: mark methods using get_status noexcept

Now that get_status returns string_view, just compare it with a const char*
rather than making a sstring out of it, and consequently, can be marked noexcept.

Signed-off-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla