PartnerAppAuthProvider class support missing in 3.x (similar to 2.x)

**Describe the feature you'd like**
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PartnerAppAuthProvider is the entity used by Sagemaker Partner AI Apps to use for their apps functionality using sagemaker python sdk.

**How would this feature be used? Please describe.**
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Please see https://github.com/aws/sagemaker-python-sdk/blob/master-v2/src/sagemaker/partner_app/auth_provider.py

**Describe alternatives you've considered**
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**Additional context**
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Commencez par lire l’implémentation référencée dans master-v2/src/sagemaker/partner_app/auth_provider.py et comparez-la avec la structure du package 3.x. Identifiez l’emplacement correspondant et les tests pour l’authentification des applications partenaires dans 3.x, puis vérifiez que PartnerAppAuthProvider est exposé et prend en charge le cas d’utilisation documenté de SageMaker Partner AI Apps.

Rédigé par le modèle d'indexation à partir du texte de l'issue.