Add toggle for editing the listing summaries for each channel

Under Summary on the listing Essentials tab, I see the Airbnb summary and Direct bookings summary. My DB summary was locked and I couldn’t edit it. I went to the Airbnb listing and selected “manage from Hospitable” but it was still locked. I didn’t know what the “Set one value” link was, so I clicked it and it “changed” to “Edit per channel”. Then both input boxes for the summaries were editable. This should be a toggle “Link both summaries” or “Edit summary for each channel”