UX: Invalid CSV error message now includes information about the malformed line (#8773)

* UX: Invalid CSV error message now includes information about the malformed line

* Update config/locales/server.en.ym and use line_number instead of lineno

Co-Authored-By: Robin Ward <robin.ward@gmail.com>

Co-authored-by: Robin Ward <robin.ward@gmail.com>

app/controllers/admin/badges_controller.rb

@@ -44,11 +44,13 @@ class Admin::BadgesController < Admin::AdminController
     raise Discourse::InvalidParameters if csv_file.try(:tempfile).nil? || badge.nil?
 
     batch_number = 1
+    line_number = 1
     batch = []
 
     File.open(csv_file) do |csv|
       csv.each_line do |email_line|
         batch.concat CSV.parse_line(email_line)
+        line_number += 1
 
         # Split the emails in batches of 200 elements.
         full_batch = csv.lineno % (BadgeGranter::MAX_ITEMS_FOR_DELTA * batch_number) == 0
@@ -64,7 +66,7 @@ class Admin::BadgesController < Admin::AdminController
 
     head :ok
   rescue CSV::MalformedCSVError
-    render_json_error I18n.t('badges.mass_award.errors.invalid_csv'), status: 400
+    render_json_error I18n.t('badges.mass_award.errors.invalid_csv', line_number: line_number), status: 400
   end
 
   def badge_types

config/locales/server.en.yml

@@ -4134,7 +4134,7 @@ en:
   badges:
     mass_award:
       errors:
-        invalid_csv: We couldn't read that CSV file. Please confirm it has one email per line.
+        invalid_csv: We encountered an error on line %{line_number}. Please confirm the CSV has one email per line.
     editor:
       name: Editor
       description: First post edit