Fix depreccated getMock in Core/Command tests

tests/Core/Command/Config/App/DeleteConfigTest.php

tests/Core/Command/Config/App/GetConfigTest.php

tests/Core/Command/Config/App/SetConfigTest.php

tests/Core/Command/Config/ImportTest.php

tests/Core/Command/Config/ListConfigsTest.php

tests/Core/Command/Config/System/DeleteConfigTest.php

tests/Core/Command/Config/System/GetConfigTest.php

tests/Core/Command/Config/System/SetConfigTest.php

tests/Core/Command/Encryption/ChangeKeyStorageRootTest.php

tests/Core/Command/Encryption/DecryptAllTest.php

tests/Core/Command/Encryption/DisableTest.php

tests/Core/Command/Encryption/EnableTest.php

tests/Core/Command/Encryption/EncryptAllTest.php

tests/Core/Command/Encryption/SetDefaultModuleTest.php

tests/Core/Command/Log/FileTest.php

tests/Core/Command/Log/ManageTest.php

tests/Core/Command/Maintenance/DataFingerprintTest.php

tests/Core/Command/Maintenance/Mimetype/UpdateDBTest.php

tests/Core/Command/Maintenance/SingleUserTest.php

tests/Core/Command/User/DeleteTest.php