monitoring-config: grafana dashboards labelValue

Since kube-prometheus-stack helm chart v32.2.0, the `labelValue` has to
be set to "1" for the default grafana dashboard label selector to select
the flux dashboard configuration.

Also, update kube-prometheus-stack to v34.7.0, latest.

Refer: https://github.com/prometheus-community/helm-charts/commit/eba5b198f597a39f2d40d3edd209dfa09429623e



Signed-off-by: Sunny <darkowlzz@protonmail.com>