Use Oauth2 exceptions in miele

[astrandb]

Proposed change

Use new Oauth2 exceptions in miele setup

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Miele: refactor to use new OAuth exceptions #175248
• This PR is related to issue:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to frontend pull request:

Checklist

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• Tests have been added to verify that the new code works.
• Any generated code has been carefully reviewed for correctness and compliance with project standards.

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[Copilot]

Pull request overview

This PR refactors the Miele integration's async_setup_entry to use Home Assistant's new OAuth2 token request exceptions instead of manually inspecting ClientResponseError.status to split 4xx/5xx handling. It resolves issue #175248 and aligns Miele with the migration pattern already adopted by integrations like google_assistant_sdk, yoto, and nest.

The new handling relies on the OAuth helper (config_entry_oauth2_flow._token_request) mapping token endpoint responses to typed exceptions: 4xx → OAuth2TokenRequestReauthError (→ ConfigEntryAuthFailed), and 429/5xx (OAuth2TokenRequestTransientError, a subclass of OAuth2TokenRequestError) plus other ClientErrors → ConfigEntryNotReady. The except-clause ordering is correct because OAuth2TokenRequestReauthError is a subclass of OAuth2TokenRequestError and is caught first. The now-unused ClientResponseError import is removed from this file (other Miele modules retain their own imports), and existing tests (401 → SETUP_ERROR, 500 → SETUP_RETRY, connection error → SETUP_RETRY) continue to cover the changed path.

Changes:

• Replace manual ClientResponseError status-splitting with typed OAuth2 exceptions in setup.
• Update imports to pull in OAuth2TokenRequestError/OAuth2TokenRequestReauthError and drop the unused ClientResponseError.

[erwindouna]

Thanks @astrandb!