Update variables according to Well-Architected Framework

[chinthakaru]

Description

Update Blob Storage variables to align with WAF recommendations

Type of Change

• [x] Non-module change (e.g. CI/CD, documentation, etc.)
• [x] Azure Verified Module updates:
  • [x] Bugfix containing backwards compatible bug fixes
  • [ ] Someone has opened a bug report issue, and I have included "Closes #{bug_report_issue_number}" in the PR description.
  • [x] The bug was found by the module author, and no one has opened an issue to report it yet.
  • [ ] Feature update backwards compatible feature updates.
  • [ ] Breaking changes.
  • [x] Update to documentation

Checklist

• [x] I'm sure there are no other open Pull Requests for the same update/change
• [x] My corresponding pipelines / checks run clean and green without any errors or warnings
• [x] I did run all pre-commit checks

[microsoft-github-policy-service[bot]]

[!IMPORTANT] The "Needs: Triage :mag:" label must be removed once the triage process is complete!

[!TIP] For additional guidance on how to triage this issue/PR, see the TF Issue Triage documentation.