fix: update required providers in resource.tf and add lifecycle ignore_changes for billing_policy_id in tests

[mawasile]

This pull request makes updates to the Power Platform billing policy resource example and its associated acceptance tests. The main changes involve how required providers are defined and how the billing_policy_id property is managed in test resources to improve test reliability.

Provider configuration updates:

• Moved the terraform block specifying required providers from terraform.tf to resource.tf, and removed the version constraint for the azurerm provider. This centralizes provider requirements and simplifies version management. [1] [2]

Acceptance test improvements:

• Updated the acceptance test for billing policy environments to use a lifecycle { ignore_changes = [billing_policy_id] } block instead of directly setting the billing_policy_id property. This change helps prevent unnecessary test failures due to external changes in the billing policy association. [1] [2] [3]

[Copilot]

Pull request overview

Updates the Power Platform billing policy resource example and acceptance tests to make provider requirements clearer in examples and to reduce test flakiness from billing policy association drift.

Changes:

• Moved terraform { required_providers { ... } } from terraform.tf into the billing policy example’s resource.tf, and removed the pinned azurerm version.
• Updated the billing policy environment acceptance test to use lifecycle { ignore_changes = [billing_policy_id] } on powerplatform_environment resources instead of setting billing_policy_id directly.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/services/licensing/resource_billing_policy_environment_test.go	Makes acceptance test configs resilient to external/side-effect changes in billing_policy_id by ignoring drift on the environment resources.
examples/resources/powerplatform_billing_policy/terraform.tf	Removes the standalone terraform block file now that provider requirements are centralized elsewhere.
examples/resources/powerplatform_billing_policy/resource.tf	Adds required_providers into the main example configuration and removes the azurerm version pin.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.70%. Comparing base (586eb3c) to head (41f399c).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1158      +/-   ##
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- Coverage   73.71%   73.70%   -0.02%     
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  Files         133      133              
  Lines       16522    16522              
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- Hits        12179    12177       -2     
- Misses       3208     3209       +1     
- Partials     1135     1136       +1     

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