relation interface name not found in juju status --relations --format json

`juju status --relations` gives:
```
Every 1,0s: juju status --color --relations darkstar: Tue May 2 09:09:47 2023

Model Controller Cloud/Region Version SLA Timestamp
clite mk8scloud microk8s/localhost 3.1.2 unsupported 09:09:47+02:00

App Version Status Scale Charm Channel Rev Address Exposed Message
alertmanager 0.25.0 active 1 alertmanager-k8s edge 69 10.152.183.30 no
catalogue active 1 catalogue-k8s edge 15 10.152.183.113 no
grafana 9.2.1 active 1 grafana-k8s edge 78 10.152.183.226 no
loki 2.7.4 active 1 loki-k8s edge 84 10.152.183.154 no
prometheus 2.42.0 active 2 prometheus-k8s edge 123 10.152.183.199 no
traefik 2.9.6 waiting 1 traefik-k8s edge 125 10.152.183.159 no installing agent

Unit Workload Agent Address Ports Message
alertmanager/0* active idle 10.1.232.152
catalogue/0* active idle 10.1.232.138
grafana/0* active idle 10.1.232.132
loki/0* active idle 10.1.232.185
prometheus/0 active idle 10.1.232.130
prometheus/1* active idle 10.1.232.186
traefik/0* waiting idle 10.1.232.133 gateway address unavailable

Offer Application Charm Rev Connected Endpoint Interface Role
alertmanager alertmanager alertmanager-k8s 69 1/1 ingress ingress requirer

Relation provider Requirer Interface Type Message
alertmanager:alerting loki:alertmanager alertmanager_dispatch regular
alertmanager:alerting prometheus:alertmanager alertmanager_dispatch regular
alertmanager:grafana-dashboard grafana:grafana-dashboard grafana_dashboard regular
alertmanager:grafana-source grafana:grafana-source grafana_datasource regular
alertmanager:replicas alertmanager:replicas alertmanager_replica peer
alertmanager:self-metrics-endpoint prometheus:metrics-endpoint prometheus_scrape regular
catalogue:catalogue alertmanager:catalogue catalogue regular
catalogue:catalogue grafana:catalogue catalogue regular
...
```

However,
`juju status --relations --format json | grep "alertmanager_dispatch"` gives null.
In other words, the interface name of the relations is nowhere to be found in the json or yaml-formatted status output.