Make Style/MapToHash aware of safe navigation operator

[koic]

Follow up #12407 (comment).

This PR makes Style/MapToHash aware of safe navigation operator.

---

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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).
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• 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.

[ydakuka]

Another false-negative for the Style/MapToHash. Sorry for the delay between examples :)

hsh = [['a', '1'], ['b', '2']]
# hsh = nil

# bad
hsh&.map { |k, v| [k, v] }.to_h

# good
hsh.to_h { |k, v| [k, v] }

[ydakuka]

And

hsh = [['a', '1'], ['b', '2']]
# hsh = nil

# bad
hsh&.to_h { |k, v| [k, v] } || {}

# good
hsh.to_h { |k,v| [k, v] }

[koic]

That case has already been addressed in this PR.

[koic]

# bad
hsh&.to_h { |k, v| [k, v] } || {}

# good
hsh.to_h { |k,v| [k, v] }

That probably isn't the responsibility of this cop.

[ydakuka]

Ok, I've created the issue.