Fix keda-metrics-apiserver ServiceMonitor port

[jkyros]

In our 2.11.2 release https://github.com/kedacore/keda-olm-operator/pull/205 we:

• retired the 9022 metrics port, and replaced it with 8080, the old http port.
• updated the service with the port name "metrics"

However:

• it looks like we missed updating the ServiceMonitor, which still references the port as "http"
• the prometheus target for keda-metrics-apiserver isn't working because it can't find a port named "http" anymore.

Therefore:

• This updates the ServiceMonitor so the servicemonitor port name matches the service port name.

Checklist

• [x] Commits are signed with Developer Certificate of Origin (DCO)

Fixes #