Remove validation for invalid interpolation keys.

* Our codebase currently supports custom interpolations keys that are
  not present in the original translation. The proper fix should
  be to make `TranslateOverride` aware of such keys.

app/models/translation_override.rb

@@ -42,7 +42,6 @@ class TranslationOverride < ActiveRecord::Base
         original_interpolation_keys = I18nInterpolationKeysFinder.find(original_text)
         new_interpolation_keys = I18nInterpolationKeysFinder.find(value)
         missing_keys = (original_interpolation_keys - new_interpolation_keys)
-        invalid_keys = (original_interpolation_keys | new_interpolation_keys) - original_interpolation_keys
 
         if missing_keys.present?
           self.errors.add(:base, I18n.t(
@@ -52,17 +51,6 @@ class TranslationOverride < ActiveRecord::Base
 
           return false
         end
-
-        invalid_keys = (original_interpolation_keys | new_interpolation_keys) - original_interpolation_keys
-
-        if invalid_keys.present?
-          self.errors.add(:base, I18n.t(
-            'activerecord.errors.models.translation_overrides.attributes.value.invalid_interpolation_keys',
-            keys: invalid_keys.join(', ')
-          ))
-
-          return false
-        end
       end
     end
 

config/locales/server.en.yml

@@ -413,7 +413,6 @@ en:
         translation_overrides:
           attributes:
             value:
-              invalid_interpolation_keys: 'The following interpolation key(s) are invalid: "%{keys}"'
               missing_interpolation_keys: 'The following interpolation key(s) are missing: "%{keys}"'
 
   user_profile:

spec/models/translation_override_spec.rb

@@ -19,19 +19,6 @@ describe TranslationOverride do
           ))
         end
       end
-
-      describe 'when interpolation keys are invalid' do
-        it 'should not be valid' do
-          translation_override = TranslationOverride.upsert!(
-            I18n.locale, 'some_key', '%{first} %{second} %{third}'
-          )
-
-          expect(translation_override.errors.full_messages).to include(I18n.t(
-            'activerecord.errors.models.translation_overrides.attributes.value.invalid_interpolation_keys',
-            keys: 'third'
-          ))
-        end
-      end
     end
   end