[16.0][Fix] ChannelManager.get_channel_by_name create wrong subchannels when pass parent_fallback=True

[lingxiezfy]

c = cm.get_channel_by_name('root.sub.not.configured', parent_fallback=True)

# c.fullname should be "root.sub.not.configured", instand of "root.sub.sub.not.configured"
assert c.fullname == "root.sub.not.configured"

[OCA-git-bot]

Hi @guewen, some modules you are maintaining are being modified, check this out!

[github-actions[bot]]

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