doc update on global.redis.password in favor of global.redis.auth

What does this MR do?

The global.redis.password is not up to date in the variable table according the global.redis.auth change.

Related issues

As I can do the fix by my own, I didn't open issues but this is linked to the following MR:

• !3140 (merged)
• !3239 (merged)

Author's checklist

• Ensure the branch name starts with docs- or ends with -docs, so only the docs-related CI jobs are included
• Consider taking the GitLab Technical Writing Fundamentals course
• Follow the:
  • Documentation process.
  • Documentation guidelines.
  • Style Guide.
• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

If you are only adding documentation, do not add any of the following labels:

• ~"feature"
• ~"frontend"
• ~"backend"
• ~"bug"
• ~"database"

These labels cause the MR to be added to code verification QA issues.

Review checklist

Documentation-related MRs should be reviewed by a Technical Writer for a non-blocking review, based on Documentation Guidelines and the Style Guide.

• If the content requires it, ensure the information is reviewed by a subject matter expert.
• Technical writer review items:
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  • Ensure the appropriate labels are added to this MR.
  • If relevant to this MR, ensure content topic type principles are in use, including:
    • The headings should be something you'd do a Google search for. Instead of Default behavior, say something like Default behavior when you close an issue.
    • The headings (other than the page title) should be active. Instead of Configuring GDK, say something like Configure GDK.
    • Any task steps should be written as a numbered list.
    • If the content still needs to be edited for topic types, you can create a follow-up issue with the docs-technical-debt label.
• Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
• Ensure a release milestone is set.