Fix backup status query (#484)

The backup status query was incorrectly changed before.
This change uses the original query as a model,
but simplifies the query based on the underlying metrics.

Notes:
- The prometheus min function takes one metric;
- The last incremental backup returns the last incr, diff, or full
- The last diff backup returns the last diff or full
- The last full backup returns the last full

This is true currently for PGO OTEL and postgres_exporter solutions.

Author: benjaminjb

changelogs/fragments/481.yml

@@ -0,0 +1,2 @@
+bugfixes:
+ - grafana - Fixed container postgresql details dashboard query for last completed backup

grafana/containers/postgresql_details.json

@@ -151,7 +151,7 @@
       "pluginVersion": "7.4.5",
       "targets": [
         {
-          "expr": "min(ccp_backrest_last_incr_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"}, ccp_backrest_last_diff_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"}, ccp_backrest_last_full_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"})",
+          "expr": "min(ccp_backrest_last_incr_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"} or ccp_backrest_last_diff_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"} or ccp_backrest_last_full_backup_time_since_completion_seconds{pg_cluster=\"[[cluster]]\"}) ",
           "format": "time_series",
           "interval": "",
           "intervalFactor": 1,