[Identity] Fix TypeError from certain Entra responses

[pvaneck]

Closes: #44234

[Copilot]

Pull request overview

This PR fixes a TypeError that occurred when Microsoft Entra ID returned certain non-JSON responses (specifically None content). The fix adds defensive handling to catch this case early and raise a more helpful ClientAuthenticationError instead of allowing the code to fail with a TypeError when trying to call .get() on None.

Key Changes

• Added early validation in _process_response to check for None/empty content before attempting to use it
• Added a test case to verify the fix handles None content properly
• Updated CHANGELOG.md to document the bug fix

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
sdk/identity/azure-identity/azure/identity/_internal/aad_client_base.py	Added if not content: check to raise ClientAuthenticationError early when response content is None or empty
sdk/identity/azure-identity/tests/test_aad_client.py	Added test_none_content_handling to verify None content is handled without TypeError
sdk/identity/azure-identity/CHANGELOG.md	Documented the bug fix with reference to PR #44258