[bitnami/redis] Fix sentinel PDB condition

[fmulero]

Description of the change

Fix mistake in the condition what enables the PodDisruptionBudgets for sentinel.

Benefits

Remove unnecessary PDB created when sentinel is not enabled.

Possible drawbacks

None

Applicable issues

• Follow up [bitnami/redis] Enable PodDisruptionBudgets #26355

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• [NA] Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[wouterh]

I believe there's something wrong with the condition for creating the master PDB too. In my configuration, it created a PDB for the masters while the master statefulset is not created:

$ kubectl -n redis get pdb -o jsonpath="{.items[].metadata.name} {.items[].spec.selector} {.items[].status.expectedPods}"
redis-master {"matchLabels":{"app.kubernetes.io/component":"master","app.kubernetes.io/instance":"redis","app.kubernetes.io/name":"redis"}} 0

$ kubectl -n redis get sts
NAME         READY   AGE
redis-node   3/3     472d