Fix Rubocop Style/IfUnlessModifier offences

What does this MR do and why?

Fix Rubocop Style/IfUnlessModifier offences.

❯ REVEAL_RUBOCOP_TODO=1 bundle exec rubocop --show-cops Style/IfUnlessModifier
# Supports --autocorrect
Style/IfUnlessModifier:
  Description: Favor modifier if/unless usage when you have a single-line body.
  StyleGuide: "#if-as-a-modifier"
  Enabled: true
  VersionAdded: '0.9'
  VersionChanged: '0.30'

The code this is MR is autocorrected by running the following commands.

$ REVEAL_RUBOCOP_TODO=1 bundle exec rubocop --only Style/IfUnlessModifier --parallel -a app/controllers/**/*.rb
❯ bundle exec rake rubocop:todo:generate[Style/IfUnlessModifier]                                                                                                                                         
Generating RuboCop TODOs with:                                                                                                                                                                  
  rubocop --parallel --format RuboCop::Formatter::TodoFormatter --only Style/IfUnlessModifier                                                                                                   
                                                                                                                                                                                                
This might take a while...                                                                                                                                                                      
Written to .rubocop_todo/style/if_unless_modifier.yml

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Before	After

How to set up and validate locally

Running this command should not result in error.

$ bundle exec rubocop --only Style/IfUnlessModifier --parallel