Replace uglifier with terser

[julianguyen]

Description

As recommended in this react/react-rails issue, switching from uglifier to terser to address the following error:

remote:        I, [2023-05-09T16:35:58.877827 #2725]  INFO -- sentry: ** [Sentry] [Transport] Sending envelope with items [event] d786d36a0e114eecbf7e33f5862d8f0e to Sentry        
remote:        Uglifier::Error: Unexpected token: keyword (const). To use ES6 syntax, harmony mode must be enabled with Uglifier.new(:harmony => true).        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/uglifier-4.1.20/lib/uglifier.rb:234:in `parse_result'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/uglifier-4.1.20/lib/uglifier.rb:216:in `run_uglifyjs'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/uglifier-4.1.20/lib/uglifier.rb:168:in `compile'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/uglifier_compressor.rb:53:in `call'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/uglifier_compressor.rb:28:in `call'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:75:in `call_processor'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:57:in `block in call_processors'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in `reverse_each'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in `call_processors'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/loader.rb:134:in `load_from_unloaded'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/loader.rb:60:in `block in load'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/loader.rb:317:in `fetch_asset_from_dependency_cache'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/loader.rb:44:in `load'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:20:in `block in initialize'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:47:in `load'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/base.rb:66:in `find_asset'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/base.rb:73:in `find_all_linked_assets'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:134:in `block in find'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:133:in `each'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:133:in `find'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:186:in `compile'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-rails-3.4.2/lib/sprockets/rails/task.rb:67:in `block (3 levels) in define'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-3.7.2/lib/rake/sprocketstask.rb:147:in `with_logger'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sprockets-rails-3.4.2/lib/sprockets/rails/task.rb:66:in `block (2 levels) in define'        
remote:        /tmp/build_bf919405/vendor/bundle/ruby/3.1.0/gems/sentry-ruby-5.9.0/lib/sentry/rake.rb:26:in `execute'

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