Remove deprecated File.exists?

In 7999ff2 the cops were disabled, but
Ruby 3.2 has removed the method.

Author: ekohl

lib/puppet/parser/functions/loadjson.rb

@@ -50,12 +50,13 @@ module Puppet::Parser::Functions
           warning("Can't load '#{url}' HTTP Error Code: '#{res.status[0]}'")
           args[1]
         end
+
         if Puppet::Util::Package.versioncmp(Puppet.version, '8.0.0').negative?
           PSON.load(contents) || args[1]
         else
           JSON.parse(contents) || args[1]
         end
-      elsif File.exist?(args[0]) # rubocop:disable Lint/DeprecatedClassMethods : Changing to .exist? breaks the code
+      elsif File.exist?(args[0])
         content = File.read(args[0])
         if Puppet::Util::Package.versioncmp(Puppet.version, '8.0.0').negative?
           PSON.load(content) || args[1]