FIX outdated default initializers in CoPyRIT

[behnam-o]

#2100 removed some initializers but did not update the initializer configurations of copyrit which is referencing some of the removed ones, resulting in errors like this on startup:

ERROR: Application startup failed. Exiting.
ValueError: Initializer 'airt' not found in registry.
Available initializers: load_default_datasets, preload_scenario_metadata, scorer, target, technique