fix: avm/res/storage-account - skip azureFilesIdentityBasedAuthentication when empty instead of null

[AVDGuy]

When deploying this template for an existing storage account, it removes the azureFilesIdentityBasedAuthentication method when azureFilesIdentityBasedAuthentication is empty. In case of AD join, where you would use the powershell module to join the storage account, the storage acocunt loses authentication method for the share.

With this fix it skips the property all together when empty.

Description

Pipeline Reference

Pipeline

Type of Change

• Update to CI Environment or utilities (Non-module affecting changes)
• Azure Verified Module updates:
  • Bugfix containing backwards-compatible bug fixes, and I have NOT bumped the MAJOR or MINOR version in version.json:
    • Someone has opened a bug report issue, and I have included "Closes #{bug_report_issue_number}" in the PR description.
    • 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, and I have bumped the MINOR version in version.json.
  • Breaking changes and I have bumped the MAJOR version in version.json.
  • Update to documentation

Checklist

• I'm sure there are no other open Pull Requests for the same update/change
• I have run Set-AVMModule locally to generate the supporting module files.
• My corresponding pipelines / checks run clean and green without any errors or warnings

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Tip

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[AlexanderSehr]

Hey @AVDGuy,
good suggestion and nice account name 😄
As per the contribution flow, there'd be a few open asks such as

• Running the Set-AVMModule utility on the module to regenerate files such as the template & readme
• Attaching a pipeline badge from a successful run
  Ultimately, it will then be @ktremain / @fblix who will review & approve the PR.