Use uglifier harmony mode to handle es6 syntax with rails 7

We were getting the following error in production mode:

```
RAILS_ENV=production bundle exec rake evm:compile_assets
...
rake aborted!
Uglifier::Error: Unexpected token: punc ((). To use ES6 syntax, harmony mode must be enabled with Uglifier.new(:harmony => true).
```

Note, this change makes all rails processes in production and test load uglifier even if they'll never
use it.  This is because we're eager loading it, instead of delay loading it via a symbol.

It sounds like we can possibly resolve this by figuring out which es6 syntax it doesn't like

See https://www.github.com/lautis/uglifier/issues/127

Author: jrafanie

lib/manageiq/ui/classic/engine.rb

@@ -37,7 +37,10 @@ class Engine < ::Rails::Engine
         config.assets.paths << root.join('vendor', 'assets', 'stylesheets').to_s
 
         if Rails.env.production? || Rails.env.test?
-          config.assets.js_compressor = :uglifier
+          # Workaround rails 7 + es6 syntax in some js causing uglifier errors by running harmony mode
+          # See: https://www.github.com/lautis/uglifier/issues/127
+          require 'uglifier'
+          config.assets.js_compressor = Uglifier.new(:harmony => true)
         end
 
         def self.vmdb_plugin?