Always log the used bundler, even for webpack (#83418)
For `next build` and `next dev`, log that webpack is used
```
▲ Next.js 15.5.1-canary.26 (webpack)
Creating an optimized production build ...
✓ Compiled successfully in 1244ms
Linting and checking validity of types ..
⚠ The Next.js plugin was not detected in your ESLint configuration. See https://nextjs.org/docs/app/api-reference/config/eslint#migrating-existing-config
✓ Linting and checking validity of types
✓ Collecting page data
✓ Generating static pages (3/3)
✓ Collecting build traces
✓ Finalizing page optimization
```
