Update WASM image

[jaredpar]

Move to an Ubuntu image which has the en_US.UTF-8 locale available.
This should remove the spurious warning that we're seeing during
PR / CI

closes #34280

[jaredpar]

Once merged builds should be completely warning free.

[jaredpar]

@ViktorHofer @safern @akoeplinger

[jaredpar]

The libraries failure was a Helix 503, re-running.

[safern]

Thanks @jaredpar. Since we're now warnings free, in order to prevent introducing new warnings, could you also remove: _warnAsErrorArg and all it's references from: https://github.com/dotnet/runtime/blob/5369c7119b0f174c2614fe4ee197bdb0c42010a1/eng/pipelines/libraries/base-job.yml as part of this change?

[jaredpar]

Since we're now warnings free, in order to prevent introducing new warnings, could you also remove: _warnAsErrorArg and all it's references from:

I will definitely do that but prefer to do as a separate PR. Given the last time I tried that I broke the outer loop wanted to have a PR where I just changed that, queued up a coulpe of the outer loop jobs and ensure I didn't break them with the warn as error change (again 😦 ).

[safern]

I think for this change you should be safe as we build the same configurations and same containers for outerloop jobs, but since you're making the change, I'll leave it up to you.