Fix Performance/MapCompact offenses for most lib/

What does this MR do and why?

Part 1 of fixing 👮 Performance/MapCompact offenses for lib/ and its specs.

Done via bundle exec rubocop -A --only Performance/MapCompact.

Note that autocorrection is unsafe so through review is required.

For example, the following examples are not equivalent:

[true, false, nil].map(&:itself).compact # => [true, false]

[true, false, nil].filter_map(&:itself) # => [true]

How to set up and validate locally

Run

bundle exec rubocop --only Performance/MapCompact --parallel
# No offense

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.