FIX: Create email token with correct scope (#15658)

`account_created` email contains a URL to `/u/password-reset/TOKEN`
which means that the correct scope for the email token is
`password_reset`, not `signup`.

lib/tasks/admin.rake

@@ -27,7 +27,7 @@ task "admin:invite", [:email] => [:environment] do |_, args|
   user.email_tokens.update_all confirmed: true
 
   puts "Sending email!"
-  email_token = user.email_tokens.create!(email: user.email, scope: EmailToken.scopes[:signup])
+  email_token = user.email_tokens.create!(email: user.email, scope: EmailToken.scopes[:password_reset])
   Jobs.enqueue(:user_email, type: :account_created, user_id: user.id, email_token: email_token.token)
 end