FIX: Show invite validation errors to users (#12717)

The server used to respond with a generic 'error, contact admin' message
which did not offer any hint what the error was. This happened even when
the error could be easily corrected by the user (for example, if they
chose a very common password).

app/controllers/invites_controller.rb

@@ -228,9 +228,7 @@ class InvitesController < ApplicationController
         end
 
         user = invite.redeem(**attrs)
-      rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotSaved => e
-        return render json: failed_json.merge(errors: e.record&.errors&.to_hash, message: I18n.t('invite.error_message')), status: 412
-      rescue Invite::UserExists => e
+      rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotSaved, Invite::UserExists => e
         return render json: failed_json.merge(message: e.message), status: 412
       end
 

config/locales/server.en.yml

@@ -239,7 +239,6 @@ en:
       <p>Otherwise please <a href="%{base_url}/password-reset">Reset Password</a>.</p>
     not_found_template_link: |
       <p>The invitation to <a href="%{base_url}">%{site_name}</a> can no longer be redeemed. Please ask the person who invited you to send you a new invitation.</p>
-    error_message: "There was an error accepting invite. Please contact the site's administrator."
     user_exists: "There's no need to invite <b>%{email}</b>, they <a href='%{base_path}/u/%{username}/summary'>already have an account!</a>"
     invalid_email: "%{email} isn't a valid email address."
     confirm_email: "<p>You’re almost done! We sent an activation mail to your email address. Please follow the instructions in the mail to activate your account.</p><p>If it doesn’t arrive, check your spam folder.</p>"

spec/requests/invites_controller_spec.rb

@@ -443,7 +443,6 @@ describe InvitesController do
       it 'does not log in the user if there are validation errors' do
         put "/invites/show/#{invite.invite_key}.json", params: { password: 'password' }
         expect(response.status).to eq(412)
-        expect(response.parsed_body['errors']['password']).to be_present
       end
 
       it 'fails when local login is disabled and no external auth is configured' do