support user assigned identity for azurerm_subscription_policy_assignment, azurerm_management_group_policy_assignment, azurerm_resource_group_policy_assignment and azurerm_resource_policy_assignment resources

[sinbai]

The purpose of this PR:

Currently, the resources for azurerm_subscription_policy_assignment, azurerm_management_group_policy_assignment, azurerm_resource_group_policy_assignment and azurerm_resource_policy_assignment only support SystemAssigned identity in terraform. To support "UserAssigned" identity in terraform as a ad hot request to PG team.

Test Results:

PASS: TestAccSubscriptionPolicyAssignment_basicWithBuiltInPolicySet (548.38s)
PASS: TestAccSubscriptionPolicyAssignment_identity (582.87s)
PASS: TestAccSubscriptionPolicyAssignment_basicWithCustomPolicy (624.55s)
PASS: TestAccSubscriptionPolicyAssignment_basicWithBuiltInPolicySetNonComplianceMessage (660.37s)
PASS: TestAccSubscriptionPolicyAssignment_basicWithCustomPolicyComplete (736.98s)
PASS: TestAccSubscriptionPolicyAssignment_basicWithBuiltInPolicyNonComplianceMessage (854.23s)
PASS: TestAccSubscriptionPolicyAssignment_basicWithBuiltInPolicy (856.30s)
PASS: TestAccResourcePolicyAssignment_basicWithCustomPolicyRequiresImport (515.01s)
PASS: TestAccResourcePolicyAssignment_identity (665.29s)
PASS: TestAccResourcePolicyAssignment_basicWithBuiltInPolicySet (702.62s)
PASS: TestAccResourcePolicyAssignment_basicWithCustomPolicy (754.82s)
PASS: TestAccResourcePolicyAssignment_basicWithBuiltInPolicySetNonComplianceMessage (828.97s)
PASS: TestAccResourcePolicyAssignment_basicWithCustomPolicyComplete (841.58s)
PASS: TestAccResourcePolicyAssignment_basicWithBuiltInPolicyNonComplianceMessage (958.69s)
PASS: TestAccResourcePolicyAssignment_basicWithBuiltInPolicy (958.96s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithCustomPolicyRequiresImport (503.99s)
PASS: TestAccResourceGroupPolicyAssignment_identity (594.68s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithBuiltInPolicySet (649.31s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithBuiltInPolicySetNonComplianceMessage (693.25s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithCustomPolicy (716.77s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithCustomPolicyComplete (814.09s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithBuiltInPolicyNonComplianceMessage (945.63s)
PASS: TestAccResourceGroupPolicyAssignment_basicWithBuiltInPolicy (945.65s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithBuiltInPolicy (899.77s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithCustomPolicyRequiresImport (471.84s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithBuiltInPolicySet (610.89s)
PASS: TestAccManagementGroupPolicyAssignment_identity (622.25s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithCustomPolicyComplete (1283.53s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithBuiltInPolicyNonComplianceMessage (699.33s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithBuiltInPolicySetNonComplianceMessage (702.01s)
PASS: TestAccManagementGroupPolicyAssignment_basicWithCustomPolicy (662.29s)
PASS: TestAccManagementGroupPolicyAssignment_basicComplexWithCustomPolicy (772.52s)

[stephybun]

Tests passed. Thanks @sinbai, LGTM 💯

[github-actions]

This functionality has been released in v3.0.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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