feat(microsoft365): add new check entra_policy_ensure_default_user_cannot_create_tenants

[HugoPBrito]

Context

In Microsoft Entra ID, non-administrative users can create new tenants, which results in them becoming the Global Administrator of that tenant. This can lead to shadow IT, where unauthorized environments are created without proper security controls, making it difficult for IT teams to manage and secure data.

Description

This check ensures that non-admin users are restricted from creating new tenants in Microsoft Entra ID. By setting this restriction to "Yes", organizations can prevent uncontrolled tenant creation, ensuring that all new tenants are properly managed and secured under IT governance.

Checklist

• Are there new checks included in this PR? Yes.
  • If so, do we need to update permissions for the provider? No.
• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.
• Review if is needed to change the Readme.md

API

• Verify if API specs need to be regenerated.
• Check if version updates are required (e.g., specs, Poetry, etc.).
• Ensure new entries are added to CHANGELOG.md, if applicable.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.70%. Comparing base (d105337) to head (2fb85f8).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6918      +/-   ##
==========================================
+ Coverage   88.67%   88.70%   +0.02%     
==========================================
  Files        1200     1201       +1     
  Lines       34646    34659      +13     
==========================================
+ Hits        30724    30745      +21     
+ Misses       3922     3914       -8     

Flag	Coverage Δ
prowler	88.70% <100.00%> (+0.02%)	⬆️

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Components	Coverage Δ
prowler	88.70% <100.00%> (+0.02%)	⬆️
api	∅ <ø> (∅)