[META] Setup page improvements

[sidvishnoi]

• [x] #614
  • [x] Make copy updates and validation improvements based on https://github.com/interledger/web-monetization-extension/issues/565
  • [x] Support fallback for copy-paste key when automatic copying key fails
• [x] Add service to automatically copy public key to the wallet / along with E2E tests for each (related)
  • [x] #615
  • [x] #616
  • [x] #617
• [x] #625
• [x] #622

Out of scope for this story:

• 618 (depends on GateHub fixing some things)

• 646

• 653