Gmail should be fine. Are you able to remove the map before you forward the email please? We believe that this is an actual attachment but Gmail isn’t showing it as such because it’s in the body of the email itself. Deleting the map should resolve it.
[Edit]
Uber can also provide you with a PDF copy of your trip details. If it’s not convenient to email these, you can also use Dropbox to pull invoices into your account.
There’s instructions on how to get a PDF copy of your trip here: