Testing configuration options that affect CLI output

[giraugh]

Started investigating a fix for #8973 and noticed that the listr output in packages/graphql-codegen-cli/src/codegen.ts is silenced during tests. As a result, testing whether output is silenced when errorsOnly is set becomes tricky. I can continue working on this without a test or investigate alternative ways of silencing logging output during other tests.

Any input is appreciated, still new to this project :)

[saihaj]

I am even happy to find alternatives to listr if you have any recommendations?