[Vanilla Bug] Cancelling Wonders (or at least Stonehenge)

While building Stonehenge, I noticed a bug (or feature). When I have Stonehenge in slot 1 of the production queue, if I right click it or drag it over to the garbage can, it cancels it outright. Doesn't matter if Stonehenge was half build, the tile is now clean, and all the production invested into it is gone. (This only happens in slot 1)

I tested it with CQUI, then reproduced the same bug without CQUI or any other mod. I'm posting this here hoping CQUI could come up with a fix (or work around) to keep us from accidentally cancelling a wonder, and all of it's production.

Stonehenge is the only wonder I tested, not sure if the issue is unique to Stonehenge, or applies to all wonders.

- OS: Windows 10
- Version: 1.0.0.290
- Expansions: All expansions and DLC, including Rise & Fall, and Gathering Storm

[Test - CQUI - 27 1920 BC.zip](https://github.com/Azurency/CQUI_Community-Edition/files/3015570/Test.-.CQUI.-.27.1920.BC.zip)

Start by reproducing the issue with Stonehenge in production queue slot 1, using right-click and the garbage-can drag action. Then trace the Lua production-queue cancellation handling and compare slot 1 with later slots. Done means cancelling a wonder no longer accidentally removes its production, with the behavior checked for Stonehenge and other wonders.

Written by the indexing model from the issue text.