"Share" on invoice screen triggers the wrong behavior (user feedback)

[agbegin]

When you create an invoice in LN cash register, user expects that "Share" will pop open the OS share functionality and share the invoice that has been created (as it works in the mobile app). Currently, it captures a link for sharing the cash register:

"Use the link embedded below to pay [username] some sats. Powered by: https://galoy.io"

Let's update so that the "share" button works as it does in the mobile app, which is that it shares the invoice. If possible, we should also include the QR image in the sharable message.

Note: this is for mobile browsers only. Desktop experience is different, and does need improvement which will be outlined in a separate GitHub issue.