Adjust external Canton test file to update snippet output split

[coldice]

Adjust Canton source test docs-open/src/sphinx/docs-cn/global-synchronizer-canton-console-advanced-operations.rst, splitting up the output of the third test:

.. snippet:: cn_global_synchronizer_canton_console_advanced_operations
    .. hidden:: participant1.parties.disable(aliceParty)
    .. success:: val aliceParty = participant1.parties.enable("Alice")
    .. success:: participant1.topology.party_to_participant_mappings.propose(party = aliceParty, newParticipants = Seq((participant2.id, ParticipantPermission.Observation)))

to generate two output lines, following the adjustments for global-synchronizer/canton-console/advanced-operations.mdx