In the release mode, the signing didn't work because the regeneratorRuntime wasn't present. This runtime was required to support async/await syntax in older JS versions. We can target more modern browsers so that the async/await syntax can be kept, which means the runtime isn't required.

https://linear.app/comm/issue/ENG-11261/connecting-dcs-never-finishes

Run the iOS app in release mode and confirm that connecting DCs works.
Also, the regeneratorRuntime isn't mentioned in the bundle anymore.