[CPT Mailer] Don't ask for already uploaded receipt in `notified_settled` email

If a receipt has already been uploaded to the transaction when we're sending the notified settled email, then let's not prompt them to upload the receipt again. We should update the copy so that it's clear that the receipt has already been uploaded. However, if they want to manage their receipt/transaction, they can click a link to do so.

It might still be handy to include the `receipt_status_hcb_codes_url` image since it has a clear green "Receipt Uploaded" that people might be visually expecting.

https://github.com/hackclub/hcb/blob/e77a739b0c7926466378d863531a7d8959305d26/app/views/canonical_pending_transaction_mailer/notify_settled.html.erb

Start with app/views/canonical_pending_transaction_mailer/notify_settled.html.erb and inspect how the notified_settled email currently handles receipt status. Confirm the receipt-uploaded case, then verify that the copy no longer prompts for an upload, explains the receipt is already uploaded, provides a transaction-management link, and retains the status image if appropriate.

Written by the indexing model from the issue text.