[Fix #11908] Support AllowedReceivers for Style/CollectionMethods

[koic]

Fixes #11908.

This PR supports AllowedReceivers for Style/CollectionMethods. For example, by setting AllowedReceivers: ['params'] in RuboCop Rails or user configuration, the following false positive for params can be prevented:

def selection_params(current, last_category = nil, params = {})
  params.merge(
    category_id: current.is_a?(Category) ? current.to_param : last_category.to_param,
    site_id: current.is_a?(Site) ? current.to_param : nil,
  ).delete_if { |_k, v| v.nil? }
end

The configuration to params is not set in the RuboCop core due to Rails specific issues. So if this approach is accepted, I will add it to RuboCop Rails's default configuration.

---

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• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
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• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[bbatsov]

Nice improvement! Thanks!