Remove a dark background to the bottom layer if the modal contains .coinbaseOverlay

[luixxiul]

Describe the issue you encountered: #4820 (comment)

Add .last to the modal overlay unless the modal contains .coinbaseOverlay. The iframe inside .coinbaseOverlay itself has the dark background.

• Brave Version: macOS

• Any related issues:

CC @willy-b

[willy-b]

Nice. You can assign this to me if you want and if it can wait until after PRs #5809 and #6039

[mrose17]

@willy-b - any luck?

[willy-b]

was going to do this after #6039 but that is still outstanding. I'm actually out of cycles for a while now, you should probably reassign this.

[mrose17]

@willy-b - understood, thanks and no worries!

[luixxiul]

I tried and I came to a conclusion that the background layer of coinbase iframe widget should be removed instead of our modal overlay. If we remove the background of modal overlay, lag occurs after clicking the button until the coinbase widget is actually rendered.

[mrose17]

i'm going to mark this as "won't fix"... for the reasons above (and awaiting the new addfunds service). thanks very much for researching it!