Make sure azure delegation key is valid when received

[jgoedeke]

Time difference between system and azure can lead to not yet valid user delegation keys. This will throw an azure.core.exceptions.HttpResponseError. Solution can be found here: https://stackoverflow.com/a/79473336

Error messages look like this:

django-1  | azure.core.exceptions.HttpResponseError: The value for one of the XML nodes is not in the correct format.
django-1  | RequestId:xxxxxxxxx-xxxxx-xxxx-xxxx-xxxxxxxxx
django-1  | Time:2025-05-26T13:40:37.7328016Z
django-1  | ErrorCode:InvalidXmlNodeValue
django-1  | xmlnodename:2025-06-02T13:40:38Z
django-1  | xmlnodevalue:2025-06-02T13:40:38Z
django-1  | Content: <?xml version="1.0" encoding="utf-8"?><Error><Code>InvalidXmlNodeValue</Code><Message>The value for one of the XML nodes is not in the correct format.
django-1  | RequestId:xxxxxxxxx-xxxxx-xxxx-xxxx-xxxxxxxxx
django-1  | Time:2025-05-26T13:40:37.7328016Z</Message><XmlNodeName>2025-06-02T13:40:38Z</XmlNodeName><XmlNodeValue>2025-06-02T13:40:38Z</XmlNodeValue></Error>

[andyp05]

see: #1525
might be better to set

key_expiry_time = now + timedelta(days=7, minutes=-10)