[wrangler] fix: switch default logging level of unstable_dev() to warn

[mrbbot]

Fixes #3362.

What this PR solves / how to test:

When running unstable_dev() in its default "test mode", the logging level was set to none. This meant any Worker startup errors or helpful warnings wouldn't be shown. This change switches the default to warn. For example, this means if you fail to include nodejs_compat and try to import node:buffer, you'll now see the following output, as opposed to an unclear failure:

Author has addressed the following:

• Tests
  • Included
  • Not necessary because:
• Changeset (Changeset guidelines)
  • Included
  • Not necessary because:
• Associated docs
  • Issue(s)/PR(s):
  • Not necessary because: we don't currently document the default logging level, and I think users would expect any errors/warnings to be surfaced.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 4acd1df

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
wrangler	Patch
@cloudflare/vitest-pool-workers	Patch

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[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-wrangler-5132

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/5132/npm-package-wrangler-5132

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-wrangler-5132 dev path/to/script.js

Additional artifacts:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-create-cloudflare-5132 --no-auto-update

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-cloudflare-kv-asset-handler-5132

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-miniflare-5132

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-cloudflare-pages-shared-5132

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8110168587/npm-package-cloudflare-vitest-pool-workers-5132

Note that these links will no longer work once the GitHub Actions artifact expires.

---

wrangler@3.30.1 includes the following runtime dependencies:

Package	Constraint	Resolved
miniflare	workspace:*	3.20240223.0
workerd	1.20240223.1	1.20240223.1
workerd --version	1.20240223.1	2024-02-23

Please ensure constraints are pinned, and miniflare/workerd minor versions match.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.37%. Comparing base (5b11492) to head (4acd1df).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5132      +/-   ##
==========================================
+ Coverage   70.32%   70.37%   +0.04%     
==========================================
  Files         298      298              
  Lines       15542    15542              
  Branches     3999     3999              
==========================================
+ Hits        10930    10937       +7     
+ Misses       4612     4605       -7     

Files	Coverage Δ
packages/wrangler/src/api/dev.ts	83.33% <100.00%> (ø)

... and 6 files with indirect coverage changes