add: error handling for get_divided_map

app/lib/pages/default_page.dart

app/lib/pages/loading_page.dart

app/lib/server_requests/init_state.dart

app/lib/widgets/main_layout.dart

server/main.py

server/map_handler/__pycache__/add_lake.cpython-311.pyc

server/map_handler/__pycache__/get_lake.cpython-311.pyc

server/map_handler/__pycache__/get_lake_data.cpython-311.pyc

...map_handler/__pycache__/get_lake_relation.cpython-311.pyc

.../map_handler/__pycache__/get_measurements.cpython-311.pyc

server/map_handler/get_lake.py

server/map_handler/get_lake_relation.py

server/map_handler/get_measurements.py

server/map_handler/lake_relations/all_lake_names.json