Revert "YAML inventory unit test: fix test inventory format (#33828)"

[gundalow]

SUMMARY

This reverts commit dfb2f34.

As yaml plugin should not be responsible for ungrouped

Original PR #33828

ISSUE TYPE

• Bugfix Pull Request

[gundalow]

rebuild_merge

[gundalow]

@pilou- FYI

[pilou-]

Then it should be inventory plugin should not be responsible for ungrouped. But there isn't such rule: for example ini, advanced_host_list and host_list handle ungrouped group.

• ansible/lib/ansible/plugins/inventory/ini.py

  Line 148 in dfb2f34

  # We behave as though the first line of the inventory is '[ungrouped]',

• ansible/lib/ansible/plugins/inventory/advanced_host_list.py

  Line 62 in dfb2f34

  self.inventory.add_host(host, group='ungrouped', port=port)

• ansible/lib/ansible/plugins/inventory/host_list.py

  Line 64 in dfb2f34

  self.inventory.add_host(host, group='ungrouped', port=port)

Meanwhile this fix doesn't broke anything, could we keep this fix waiting for a more global inventory plugin should not be responsible for ungrouped fix ?

[bcoca]

correct fix in #33878