adjust task name to "Set node id fact"

[hcoyote]

redpanda-ansible-collection/roles/redpanda_broker/tasks/start-redpanda.yml

Line 111 in 6553162

- name: Set node id

mostly a clarity thing since you can set the explicit broker id, but we usually don't want people to do that. This has probably been labeled this way for a long time. probably best to make it clear that we're getting the node id for use in ansible, not somuch that we're enforcing the node id to be something specific