fix: update sheet header to show back instead of close in action popup

[pete-watters]

I'm opening this issue as a follow up to work on this leather-io/extension#5802

@mica000: recorded this loom to demonstrate issues with headers in action popups:
https://trustmachines.slack.com/archives/C05LRS7G44R/p1724349131407629?thread_ts=1724305603.462199&cid=C05LRS7G44R

The basic thing to change is that the Receive sheet should show a <- button instead of an X when in action popup mode.

Right now things work correctly for Send as thats actually a page and not a sheet.

[pete-watters]

@mica000 @fabric-8 : I need some advice on this. Do you want me to update all of the sheets so that they show <- when in the extension action popup?

We have many sheets and none of them are doing this right now:
https://github.com/user-attachments/assets/cb251c8b-6acd-4dcf-8391-2dd819d92375

The only place we do it is in the send flow as that's not using a sheet component. I can update it so they all follow the same approach? Or else pick some sheets like Receive.

I show in the video the example of Sign out which should also maybe show <- in action popup mode

@mica000 you can also see here that opening Receive / Send in the action popup opens it there and not in full page so I'm not sure what was happening in your video. Hopefully something that is fixed now.

CC @markmhendrickson in case you have input here

[pete-watters]

@mica000 assigning this to you as I'm not sure if we want to do this or not - updating all of the action popups to have back instead of close