chore(deps): update container image bitnami/alertmanager to 0.26.0@537c5f5 by renovate (#18200)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| bitnami/alertmanager | digest | `130b6ff` -> `537c5f5` |

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> [!WARNING]
> Some dependencies could not be looked up. Check the Dependency
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This PR has been generated by [Renovate
Bot](https://togithub.com/renovatebot/renovate).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4xODMuMiIsInVwZGF0ZWRJblZlciI6IjM3LjE4My4yIiwidGFyZ2V0QnJhbmNoIjoibWFzdGVyIn0=-->

charts/enterprise/prometheus/Chart.yaml

@@ -47,7 +47,7 @@ sources:
   - https://github.com/prometheus-operator/kube-prometheus
   - https://github.com/truecharts/charts/tree/master/charts/enterprise/prometheus
   - https://quay.io/thanos/thanos
-  - https://hub.docker.com/r/bitnami/alertmanager
   - https://hub.docker.com/r/bitnami/prometheus
+  - https://hub.docker.com/r/bitnami/alertmanager
 type: application
-version: 16.4.7
+version: 16.4.8

charts/enterprise/prometheus/values.yaml

@@ -6,7 +6,7 @@ thanosImage:
   tag: v0.34.0@sha256:2356a5f131fd80965d7a0617b70b14e4facae1aee5ec43f117f8bfbe20d987fc
 alertmanagerImage:
   repository: bitnami/alertmanager
-  tag: 0.26.0@sha256:130b6ff598e4c6975ace7c10c1913d797d39e7ab86c4a0cdb5a72802122b2bb2
+  tag: 0.26.0@sha256:537c5f5b35feda7b78899ce196f3b1fbc637677b8345c0f8817384a377e7a282
 global:
   labels: {}
 workload: