Fix a false positive for Layout/SingleLineBlockChain

[koic]

This PR fixes the following incorrect auto-correct for Layout/SingleLineBlockChain when method call chained on a new line after a single line block with trailing dot.

It also fixes the following incorrect auto-correction between Layout/SingleLineBlockChain and Layout/DotPosition cops.

% cat example.rb
example.select { |item| item.cond? }.
        join('-')
% ruby -c example.rb
Syntax OK
% bundle exec rubocop -a --only Layout/DotPosition,Layout/SingleLineBlockChain example.rb

% cat example.rb
example.select { |item| item.cond? }

        .join('-')
% ruby -c example.rb
example.rb:3: syntax error, unexpected '.', expecting end-of-input
        .join('-')

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• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• 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.