Fix crash translating an already translated text

The page was crashing when at least part of the content of the page had
been translated between the request showing the remote translations
button and the moment people pressed the button.

app/models/remote_translation.rb

@@ -31,11 +31,11 @@ class RemoteTranslation < ApplicationRecord
   def self.create_all(remote_translations_params)
     remote_translations_params.map do |remote_translation_params|
       new(remote_translation_params)
-    end.reject(&:enqueued?).each(&:save!)
+    end.reject(&:already_translated?).reject(&:enqueued?).each(&:save!)
   end
 
   def already_translated_resource
-    if remote_translatable&.translations&.where(locale: locale).present?
+    if already_translated?
       errors.add(:locale, :already_translated)
     end
   end
@@ -45,4 +45,8 @@ class RemoteTranslation < ApplicationRecord
                      locale: locale,
                      error_message: nil).any?
   end
+
+  def already_translated?
+    remote_translatable&.translations&.where(locale: locale).present?
+  end
 end

spec/shared/system/remotely_translatable.rb

@@ -1,3 +1,5 @@
+require "sessions_helper"
+
 shared_examples "remotely_translatable" do |factory_name, path_name, path_arguments|
   let(:arguments) do
     path_arguments.transform_values { |path_to_value| resource.send(path_to_value) }
@@ -192,6 +194,32 @@ shared_examples "remotely_translatable" do |factory_name, path_name, path_argume
         expect(RemoteTranslation.count).to eq(0)
         expect(resource.translations.count).to eq(2)
       end
+
+      scenario "request a translation of an already translated text" do
+        microsoft_translate_client_response = generate_response(resource)
+        expect_any_instance_of(RemoteTranslations::Microsoft::Client).to receive(:call).and_return(microsoft_translate_client_response)
+
+        in_browser(:one) do
+          visit path
+          select "Español", from: "Language:"
+
+          expect(page).to have_button "Traducir página"
+        end
+
+        in_browser(:two) do
+          visit path
+          select "Español", from: "Language:"
+          click_button "Traducir página"
+
+          expect(page).to have_content "Se han solicitado correctamente las traducciones"
+        end
+
+        in_browser(:one) do
+          click_button "Traducir página"
+
+          expect(page).not_to have_button "Traducir página"
+        end
+      end
     end
   end
 end