Fix command in telemetry installation

[syntxerror]

There are missing/incorrect commands in the Install Telemetry Backend helm steps in the documentation
helm install my-release --namespace open-match open-match/open-match \ --set open-match-override.enabled=true \ # Install the default override configmap --set open-match-telemetry.enabled=true \ # Enable telemetry logic in Open Match core --set global.telemetry.jaeger.enabled

should be set to
--set global.telemetry.jaeger.enabled

And there are missing steps to install Prometheus and Grafana in the helm section