fix: fix extra volumes indentation for rendering the helm chart properly

[soyji]

Fixes #651

Motivation

The goal is to fix a indentation issue causing the dekaf deployment helm template not to render properly when setting extra volumes, this is useful when you mount a jwt token for authenticating with dekaf

Modifications

Set the identation from 8 to 6

Verifying this change

Go to pulsar-helm-chart/charts/pulsar

Create test-values.yaml:

components:
  dekaf: true

dekaf:
  persistence:
    storageClass: "gp3"
  deployment:
    extraEnv:
    - name: DEKAF_PUBLIC_BASE_URL
      value: "http://dekaf-int-dev.test.com"
    extraVolumeMounts:
      - name: admin-token
        mountPath: /pulsar/tokens/admin
        readOnly: true
    extraVolumes:
      - name: admin-token
        secret:
          secretName: pulsar-token-admin

Running helm template pulsar . -f test-values.yaml --show-only templates/dekaf-deployment.yaml renders properly

[lhotari]

Thanks for the contribution!