Add an option to exclude a list of classes

[rachelt44]

Is your feature request related to a problem? Please describe.

We currently have an option to target specific classes via the target_class_list config option. We need a similar option for excluded specific classes, in case only a few classes need to be excluded, either because they are not affected by the changes of because of issues encountered in test generation for them.

Describe the solution you'd like

Add an excluded_class_list config option. Any class appearing in them will be excluded from the target list for test generation.

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

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