The `--test-coverage-exclude` flag is ignored when added to the extension parameters

[Ibby-B]

Hi,

Thanks for your work on this extension.
I've tried to pass the --test-coverage-exclude cli flag to the nodejs-testing.extensions's parameter config option, but it doesn't seem to have the intended effect.

I think i can fix this by passing the cli arguments here:

nodejs-testing/src/coverage.ts

Line 36 in ee39d46

(report as any).exclude.exclude.push("**/runner-loader.js");

I can try putting together a PR to make the coverage reporter aware of the flag, but I'm not sure what the contribution process is.