Prevent the "import/no-duplicates" warning for the externalization process

[eason9487]

Changes proposed in this Pull Request:

Quotes from @ecgan's #1834 (comment):

Three of the external-components files have eslint warnings that say "node_modules/@wordpress/components/build-module/index.js' imported multiple times. eslint import/no-duplicates", because we have imports from both @wordpress/components and extracted/@wordpress/components. See screenshot below:

This PR changes to use the "no-duplicate-imports" rule to prevent the warnings.

Screenshots:

It can still find the basic duplicated imports:

Detailed test instructions:

1. npm run lint:js
2. Check if there are no "import/no-duplicates" warnings.

Additional details:

"no-duplicate-imports" doesn't do the actual file path resolving, so something like import Foo from '. /foo' and import Foo from '. /foo.js' are not recognized as duplicates.

However, such rules are for code clearer purposes only, and these undetected duplicates should not cause errors.

Changelog entry

[puntope]

Thanks @eason9487

When I run the lint I cannot see anymore the warnings.