Fixed AccountClient U2M OAuth2 auth when using `external-browser` auth type

[green2k]

Instantiating AccountClient like this:

from databricks.sdk import AccountClient

dac = AccountClient(
    host="https://accounts.cloud.databricks.com",
    account_id="<DATABRICKS_ACCOUNT_ID>",
    auth_type="external-browser",
)

leads to an error:

Error code: 400

Message: unsupported_response_type.

Error code explanation: 400 - Unsupported response type: response_type=code response_mode=query.

Changes

OIDC endpoints now contains the information about the Databricks Account ID.

Tests

• [ ] make test run locally
• [ ] make fmt applied
• [ ] relevant integration tests applied