Steps to reproduce

1. Create a demo Flutter app using the latest bootstrap, using the following flutter_bootstrap.js

   {{flutter_js}}
   {{flutter_build_config}}
   
   _flutter.loader.load({
     config: {
       renderer: 'canvaskit',
     },
   });

2. Attempt to flutter run
3. Observe the following error in the browser:

   Uncaught (in promise) FlutterLoader could not find a build compatible with configuration and environment.
   

Expected results

I'd expect the app to run.

Actual results

It seems that when not specifying a --web-renderer in the command-line, the flutter_build_config variable does not populate information for the html or canvaskit renderers, only auto; making the renderer run-time JS Parameter useless.

Code sample

(Included above)

Screenshots or Video

N/A

Logs

N/A

Flutter Doctor output

This reproduces in the latest master, and probably has always reproduced since we introduced the new load API.