Fix asserts for called once in Python 3.12

[hroncok]

Description

This fixes:

    E               AttributeError: 'called_with' is not a valid assertion. Use a spec for the mock if 'called_with' is meant to be an attribute.

    FAILED tests/TestOAuth2.py::test_refreshAccessTokenSuccess - AttributeError: ...
    FAILED tests/TestOAuth2.py::test_refreshAccessTokenFailed - AttributeError: '...
    FAILED tests/API/TestAccount.py::test_errorLoginState - AttributeError: 'call...
    FAILED tests/Settings/TestCuraStackBuilder.py::test_createMachineWithUnknownDefinition

Unfortunately, some assertions failed when the invocation was fixed. Hecen a draft.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Printer definition file(s)
• Translations

How Has This Been Tested?

• I built the package in Fedora 39 with Python 3.12.0b3

Test Configuration:

• Operating System: Fedora 39

Checklist:

• My code follows the style guidelines of this project as described in UltiMaker Meta and Cura QML best practices
• I have read the Contribution guide
• I have commented my code, particularly in hard-to-understand areas
• I have uploaded any files required to test this change