Replaced Karma with Vitest in generated package

[psmyrek]

Suggested merge commit message (convention)

Other (generator): Replaced Karma with Vitest as the testing framework in the generated package.

Other (tools): Removed support for the --coverage (-c) and --source-map (-s) flags.

Other (tools): Removed test script from the tools, because unit tests in the generated package are executed now directly by Vitest.

MINOR BREAKING CHANGE (generator): The generated package no longer uses Karma as the test runner. Instead, Vitest is used.

MINOR BREAKING CHANGE (tools): The test script is removed, because unit tests in the generated package are executed directly by Vitest. Hence, the previous custom support for the --coverage (-c) and --source-map (-s) flags is no longer needed and has been also removed. The yarn run test (or npm run test) script is still available in the generated package, but it executes Vitest. See CLI flags supported in Vitest.

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Additional information

Closes https://github.com/cksource/ckeditor5-internal/issues/3756.

Supported scopes

• generator → https://www.npmjs.com/package/ckeditor5-package-generator
• * → https://www.npmjs.com/package/@ckeditor/ckeditor5-package-*

[psmyrek]

Watch mode is now disabled in tests in the generated package. It can be enabled with --watch (-w) flag.

[pomek]

@psmyrek, should we update CKEditor 5 docs?

• https://ckeditor.com/docs/ckeditor5/latest/framework/develpment-tools/package-generator/javascript-package.html
• https://ckeditor.com/docs/ckeditor5/latest/framework/develpment-tools/package-generator/typescript-package.html

[psmyrek]

PR with updates in the CKEditor 5 docs: https://github.com/ckeditor/ckeditor5/pull/17051