Revert ConfigItem type to is_string: false

Author: spencertransier

lib/fastlane/plugin/wpmreleasetoolkit/actions/common/gp_downloadmetadata_action.rb

@@ -59,7 +59,7 @@ def self.available_options
           FastlaneCore::ConfigItem.new(key: :locales,
                                        env_name: 'FL_DOWNLOAD_METADATA_LOCALES',
                                        description: 'The hash with the GlotPress locale and the project locale association',
-                                       type: Hash),
+                                       is_string: false),
           FastlaneCore::ConfigItem.new(key: :source_locale,
                                        env_name: 'FL_DOWNLOAD_METADATA_SOURCE_LOCALE',
                                        description: 'The source locale code',