* .maintain/monitoring: Update substrate prometheus alert rules
* match the `substrate_` metrics prefix in alerts instead of `polkadot_`, following changes in #9543
* remove the filtering on polkadot|kusama domain for NumberOfFileDescriptorsHigh alert
* .maintain/monitoring: Update substrate Grafana dashboards
* match the `substrate_` metrics prefix instead of `polkadot_` in dashboards, following changes in #9543
* .maintain/monitoring: make the NumberOfFileDescriptorsHigh alert only apply for metrics tagged with 'chain'