docs: Update known issues with Azure PowerShell v13.0.0

[oZakari]

Overview/Summary

This pull request includes updates to the docs/wiki/KnownIssues.md file to clarify and expand on an existing known issue related to deployment failures with Azure PowerShell version 13.0.0. The changes provide more detailed information about the issue, its impact, and the workaround for both Azure DevOps and GitHub Actions.

Clarifications and updates to known issues:

• Updated the description of Issue 1 to include deployment failures when using Azure PowerShell version 13.0.0 locally, in addition to Azure DevOps Agents and GitHub Actions workflows.
• Expanded the list of affected modules to include ALZ Default Policy Definitions and ALZ Custom Role Definitions.
• Clarified the workaround instructions for pinning a specific Az version in the AzurePowerShell task for both Azure DevOps and GitHub Actions. [1] [2]
• Provided YAML configuration examples for both Azure DevOps and GitHub Actions to demonstrate how to pin the Az version to 12.5.0. [1] [2]

Related Issues/Work Items

This PR fixes/adds/changes/removes

Related to #907

Breaking Changes

None

Testing Evidence

Replace this with any testing evidence to show that your Pull Request works/fixes as described and planned (include screenshots, if appropriate).

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Ensured the resource API versions in .bicep file/s I am adding/editing are using the latest API version possible
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• (ALZ Bicep Core Team Only) Associated it with relevant ADO Items
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated one or more of the following tests (if required)
  • Unit
  • Linting
  • E2E (End-To-End)
  • ValidateAzCloud (Base validation in Azure Cloud)
  • ValidateMcCloud (Base validation in Azure China Cloud)
• Updated relevant and associated documentation (e.g. Contribution Guide, Module READMEs, Wiki Docs etc.)
• If relevant, created or updated Code Tours here