[App Configuration] - Head request support

[mrm9084]

Description

Adds a way to check for app config changes via head request.

See JS version: Azure/azure-sdk-for-js#36959

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

Adds a HEAD-based “check” API to Azure App Configuration’s Python client to support efficient change detection via page-level ETags (mirroring the JS SDK behavior).

Changes:

• Introduces check_configuration_settings() on sync and async clients, backed by new generated HEAD operations.
• Refactors generated paging/request preparation helpers and adds check_key_values_in_one_page implementations.
• Adds new sync/async AAD tests plus a new usage sample; updates changelog and test recordings assets tag.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
sdk/appconfiguration/azure-appconfiguration/azure/appconfiguration/_azure_appconfiguration_client.py	Adds sync check_configuration_settings() surface.
sdk/appconfiguration/azure-appconfiguration/azure/appconfiguration/aio/_azure_appconfiguration_client_async.py	Adds async check_configuration_settings() surface.
sdk/appconfiguration/azure-appconfiguration/azure/appconfiguration/_generated/_operations/_patch.py	Adds sync generated HEAD operation + shared request/error-map helpers.
sdk/appconfiguration/azure-appconfiguration/azure/appconfiguration/_generated/aio/_operations/_patch.py	Adds async generated HEAD operation + shared request/error-map helpers.
sdk/appconfiguration/azure-appconfiguration/tests/test_azure_appconfiguration_client_aad.py	Adds sync AAD test covering page-level ETag monitoring via HEAD.
sdk/appconfiguration/azure-appconfiguration/tests/test_azure_appconfiguration_client_aad_async.py	Adds async AAD test covering page-level ETag monitoring via HEAD.
sdk/appconfiguration/azure-appconfiguration/samples/check_configuration_settings_sample.py	New sample demonstrating HEAD-based change checks via ETags.
sdk/appconfiguration/azure-appconfiguration/CHANGELOG.md	Documents the new check_configuration_settings() feature.
sdk/appconfiguration/azure-appconfiguration/assets.json	Updates assets tag for new recordings.