[Fix] CES alarm rule v2 resources tag

[anton-sidelnikov]

What this PR does / why we need it

API wants explicitly to receive empty list if nothing are set

Which issue this PR fixes

Special notes for your reviewer

=== RUN   TestAlarmsCRUD
    alarms_test.go:17: Attempting to create alarm rule
    alarms_test.go:57: Attempting to get alarm rule
    alarms_test.go:66: Attempting to enable alarm rule
    alarms_test.go:73: Attempting to verify alarm rule is enabled
    alarms_test.go:80: Attempting to disable alarm rule
    alarms_test.go:50: Attempting to delete alarm rule
--- PASS: TestAlarmsCRUD (2.12s)
=== RUN   TestAlarmsCreateEventSysWithEmptyResources
    alarms_test.go:94: Attempting to create EVENT.SYS alarm rule with empty resources
    alarms_test.go:128: Attempting to verify EVENT.SYS alarm rule
    alarms_test.go:121: Attempting to delete EVENT.SYS alarm rule
--- PASS: TestAlarmsCreateEventSysWithEmptyResources (1.20s)
PASS

Process finished with the exit code 0