(breaking) Change default for `sourcemaps.ignore` to `["node_modules"]`

[s1gr1d]

Currently, the CLI applies defaults for the ignore value. To align the behavior better, we would move this default decision one level up to the bundler plugins.

How it is currently:

CLI	Bundler Plugins	Meta-Framework SDK
adds 'node_modules' as default	uses CLI in plugin manager (no defaults)	uses bundler plugins (no defaults)

More context on this in this thread: #836 (comment)

[linear]

BUNDLER-94