Make duplicate operations error a failing error

[JakeDawkins]

This PR aims to fix an issue where some users are pushing client code that errors because the error notifying users of duplicate client operation names doesn't exit appropriately.

the previous error, just told users that duplicate operations aren't permitted in client projects, but never actually enforced that as it should have. This PR should fix that behavior.

TODO:

• Update CHANGELOG.md* with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

*Make sure changelog entries note which project(s) has been affected. See older entries for examples on what this looks like.

[mgeraci]

So moving contents/documents/documentDidChange out of the try block causes the whole command to exit with an error? That's perfect!

[JakeDawkins]

I believe this is good to go, so I'm gonna give it a merge and minor release.

I tested manually with client:push and client:check and verified it failed both before trying to actually run the operation (which is what we want).

I think this error could be cleaned up (as right now it's a very unfriendly format when it's output), potentially even as a step on client:* commands, but as for right now, I think that work would be best pushed to a major, since it'd require reworking the project loading as well as VS Code errors a bit.