Wallet: QR dialog design tweaks to layout and aesthetics

[benjthayer]

The existing designs for the QR code have been updated to make them aesthetically more pleasing, leverage more standard design system components as well as making network preference handling more extensible.

The main changes are as follows:

• General tweaks to alignment / balancing in padding
• White backing, replacing the old grey backing
• Account icon in middle of QR
• Alignment of the network tags to base of QR - this means they can wrap onto multiple lines (previous designs has 2 lists left and right of the WR)
• Smaller, cleaner copy button
• Neater, narrower network list

Figma:
https://www.figma.com/file/FkFClTCYKf83RJWoifWgoX/Wallet-v2?type=design&node-id=20734-337595&mode=design&t=2O68lxNGG9g1b1tx-4

The previous design has been retained here for reference:
https://www.figma.com/file/FkFClTCYKf83RJWoifWgoX/Wallet-v2?type=design&node-id=21242-170489&mode=design&t=2O68lxNGG9g1b1tx-4