add support for AZURE_STORAGE_TOKEN in environment variable

[djouallah]

the main authentication mode in Onelake is using env AZURE_STORAGE_TOKEN, which is not supported by azure identity

https://github.com/Azure/azure-sdk-for-cpp/blob/azure-identity_1.6.0/sdk/identity/azure-identity/README.md#environment-variables

I use this with duckdb and it works great in my laptop as I have the azure cli installed

CREATE or replace PERSISTENT SECRET onelake (TYPE azure,PROVIDER credential_chain,ACCOUNT_NAME 'onelake');

the same code broke in Fabric Python notebook as there is no cli and the only available option is environment variable AZURE_STORAGE_TOKEN

[github-actions]

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