The host-metering client doesn't always set the "support" label when reporting metrics.  When swatch queries prometheus, it only includes metrics whose support labels matches  one of these values: Premium|Standard|Self-Support|None

Context thread: https://redhat-internal.slack.com/archives/C05ET70H9MX/p1706021017647579 

Done Criteria:

• Hourly metrics gathering should include instances where the support label is missing or an empty string
• These metrics should be treated as "Premium", applied by the value of defaults.sla from the RHEL_for_x86_els_payg.yaml product configuration.