Update test runner to use the new path for example implementation

[devkabiir]

Per #298, example implementations are moved from lib/example.dart to .meta/lib/example.dart. This breaks the existing test runner.

Relevant:

• dart/test/exercises_test.dart

  Line 69 in 8ec254f

  File example = File('lib/example.dart');

  .

[iHiD]

@devkabiir Is this as simple as changing the line you specified (and the one a few lines down), or is there something more complex that needs doing?

[devkabiir]

Yes it should work see #300.

But there's also #296 blocking the Test workflow from running altogether. To unblock Test, relevant lines that need to be removed are https://github.com/exercism/dart/blob/main/bin/check_formatting.dart#L8-L17

And finally the following line might need updating as well, since I don't know if the latest version of configlet supports the configlet fmt . command.

dart/bin/presubmit.dart

Line 9 in c871761

await utils.runCmdIfExecutable('bin/configlet', ['fmt', '.']);

These are quite simple changes, but I can't approve my own PR.

[iHiD]

If you tag @exercism/maintainers-admin into any PRs, Erik will approve them for you :)