Add "Pop Window" display option for Brave Wallet

[lukemulks]

Description

There's a really excellent feature for the Backpack wallet that lets the user "Pop Window", basically popping the Wallet UX out from either the extension display or the brave://wallet UI into a separate window.

I've been playing with this quite a bit, and it's really handy to have the entire wallet UX/UI as a separate window, instead of having to toggle to and from the extension panel, or to another tab among a sea of tabs in my window.

I haven't played with this with dapps yet, but suspect there may be some wins there. It almost treats the wallet UX as a separate app with this context, and feels very sidecar without the attachment.

Surfacing it here for feature request consideration. @jamesmudgett @husobee

Steps to Reproduce

1. Install the backpack extension
2. Click the account/avatar icon in upper right corner
3. Select "Pop Window" menu option (has a CTRL+G shortcut)

Actual result:

Expected result:

Reproduces how often:

Brave version (info found on brave://version)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the dev channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

[lukemulks]

Forgot to add another cool note about this feature.

When you Pop Window, the popped window gets it's own icon in the OS taskbar, separate from the primary browser icon. This makes it even easier to find the Wallet.