Add unit tests for the GÉANT IP modification workflow

gso/workflows/geant_ip/modify_geant_ip.py

test/cli/test_imports.py

test/conftest.py

test/fixtures/edge_port_fixtures.py

test/fixtures/geant_ip_fixtures.py

test/workflows/edge_port/test_create_imported_edge_port.py

test/workflows/geant_ip/test_create_geant_ip.py

test/workflows/geant_ip/test_modify_geant_ip.py

test/workflows/router/test_modify_connection_strategy.py