DEV: Fix methods removed in Ruby 3.2 (#15459)

* File.exists? is deprecated and removed in Ruby 3.2 in favor of
File.exist?
* Dir.exists? is deprecated and removed in Ruby 3.2 in favor of
Dir.exist?

script/import_scripts/friendsmegplus.rb

@@ -178,7 +178,7 @@ class ImportScripts::FMGP < ImportScripts::Base
   end
 
   def load_fmgp_json(filename)
-    raise RuntimeError.new("File #{filename} not found") if !File.exists?(filename)
+    raise RuntimeError.new("File #{filename} not found") if !File.exist?(filename)
     JSON.parse(File.read(filename))
   end