feat: ignore false/null/undefined plugins

[alexander-akait]

Part of webpack/webpack-cli#3836

Allow to use:

// `false` value for an example, for example when you are in development mode and don't want to use plugin
// so you don't need to use `.filter(Boolean)`, it is faster and has a better DX
const isProduction = false; 

module.exports = {
  //...
  resolve: {
    plugins: [
      isProduction && new DirectoryNamedWebpackPlugin()
    ],
  },
};

Note - you an use any falsy values, NaN is falsy too, but microsoft/TypeScript#15135, and I don't think it is a good idea allow to pass NaN

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@3c3d31e). Click here to learn what that means.
Patch coverage: 100.00% of modified lines in pull request are covered.

❗ Current head f5677bc differs from pull request most recent head 3a765d9. Consider uploading reports for the commit 3a765d9 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #389   +/-   ##
=======================================
  Coverage        ?   92.85%           
=======================================
  Files           ?       43           
  Lines           ?     2042           
  Branches        ?      598           
=======================================
  Hits            ?     1896           
  Misses          ?      118           
  Partials        ?       28           

Impacted Files	Coverage Δ
lib/ResolverFactory.js	96.15% <100.00%> (ø)

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