Upgrade Metabase to v0.50.26.1

[ohrite]

Description

Metabase is currently out of date (0.48 vs v0.50) and the Slack integration surfaces a warning.

Resolves #3451

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Documentation

How has this been tested?

This PR was tested according to the steps documented in runbooks/workflow/upgrade-metabase.md

Post-merge follow-ups

The new version will need to be rolled out to the cluster.

• [ ] No action required
• [x] Actions required

[github-actions[bot]]

The following changes will be applied to the production Kubernetes cluster upon merge.

BE AWARE this may not reveal changes that have been manually applied to the cluster getting undone—applying manual changes to the cluster should be avoided.

metabase, metabase, Deployment (apps) has changed:
...
        labels:
          name: metabase
      spec:
        containers:
          - name: metabase
-           image: metabase/metabase:v0.48.3
+           image: metabase/metabase:v0.50.26.1
            envFrom:
              - configMapRef:
                  name: metabase-config
            ports:
            - containerPort: 3000
...
metabase-test, metabase, Deployment (apps) has changed:
...
        labels:
          name: metabase
      spec:
        containers:
          - name: metabase
-           image: metabase/metabase:v0.48.3
+           image: metabase/metabase:v0.50.26.1
            envFrom:
              - configMapRef:
                  name: metabase-config
            ports:
            - containerPort: 3000
...