Refactor error handling to stop execution on errors

[1000hz]

Fixes #160

This PR refactors the way errors are propagated through the action when encountered. Previously, the action relied solely on core.setFailed() to handle errors, but this only sets the action status while allowing execution to continue. You can see this occur in https://github.com/cloudflare/wrangler-action/actions/runs/5968662403/job/16192935017#step:9:22, where the secret upload step failed, but the action proceeded to deploy the worker anyway.

Now instead of calling core.setFailed() at the source of every failure case, we throw errors and catch them at the top level where we then output the error and call core.setFailed().

This PR also:

• tweaks a few error messages to be more descriptive.
• removes a couple of places where the same errors were being handled at multiple levels.
• adds finally blocks around some endGroup() calls to ensure no groups are left dangling open if an error occurs.
• moves the unit-tested modules into their own file, preventing the main() call at the top-level scope of index.ts being invoked when running the unit tests.
• fixes the tsconfig module resolution setting to allow import specifiers without file extensions (moduleResolution: "Bundler")
• removes incorrect usage of prettier argument --ignore-path
• adds a workaround for a failing test workflow due to Action fails on first deployment if secrets are used #162

[JacobMGEvans]

This seems like a premature abstraction, the file is far from being large and colocating the functions means not having to jump around files.

[1000hz]

Importing anything from index.ts has the side-effect of executing the action since main() is executed in top-level scope. This meant that running the vitest test suite to test these util functions was inadvertently executing the entire action. Pulling these into their own file felt like the least disruptive way around that, especially since they’re already being unit tested in isolation. Alternatively I could have renamed index.ts to main.ts and added a new index.ts that just imports and executes main(), but that would have made this PR harder to review and I didn’t want to make the diff any noisier than it’s already become.

[JacobMGEvans]

Oh that is cool! I didnt see they had a new moduleResolution bundler