Merge branch 'feature/cost_estimation_delete_read_flights_per_year' into 'main'

Deleted input of `flights_per_year` from acXML

See merge request !239

cost_estimation/src/tube_and_wing/empirical/operating_cost_estimation_tu_berlin/usermethoddatapreparation.py

@@ -81,8 +81,7 @@ def user_method_data_input_preparation(routing_dict):
         'seat_load_factor_study':
             [requirements_path + 'study_mission/payload_fractions/passenger_mass_fraction', float],
         'flight_time_design': [mission_path + 'design_mission/flight_time', float],
-        'flight_time_study': [mission_path + 'study_mission/flight_time', float],
-        'flights_per_year': [assessment_scenario_path + 'flights_per_year', float]
+        'flight_time_study': [mission_path + 'study_mission/flight_time', float]
     }
 
     """Module configuration file."""