Fix date parser for missing ms

[fishi0x01]

Dynatrace API does not return milliseconds if they are 000, e.g., 2025-01-18T21:35:03.000Z gets converted to 2025-01-18T21:35:03Z

That leads to the following error in the client API:

ValueError("time data '2025-01-18T21:35:03Z' does not match format '%Y-%m-%dT%H:%M:%S.%fZ'")

This might be an issue in the API itself, but for now we can mitigate it by accepting both ISO pattern (with and without ms).

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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