[bitnami/kafka] Fix 'sasl.client.passwords' not working during chart upgrade

[migruiz4]

Description of the change

Fixes an issue where the value sasl.client.passwords would be ignored if set during chart upgrade.

Applicable issues

• fixes [bitnami/kafka] kafka user passwords #26610

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• 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)

[dgomezleon]

LGTM

[migruiz4]

Tested using the following values:

  client:
    users:
      - user1
      - user2
    passwords: "pass1,pass2"


==>

  client:
    users:
      - user1
      - user2
    passwords: "newpass1,newpass2"

Result:

$ k get secrets kafka-user-passwords -o jsonpath='{.data.client-passwords}' | base64 -d
pass1,pass2% 
$ helm upgrade kafka bitnami/kafka  -f values.yaml
...                                            
$ k get secrets kafka-user-passwords -o jsonpath='{.data.client-passwords}' | base64 -d
newpass1,newpass2