Determine extension currency from the wallet

[tselit]

Context

The WM extension must determine the currency that it displays based on the currency denomination of the connected wallet.

TODOs

• The extension uses a default currency symbol for the US dollar $
• When a user connects their wallet to the extension, the extension must obtain & use the currency of the connected wallet.
• This applies to the following form fields:
  • On the 'connect wallet' Settings page, the currency of the Amount
  • On the 'disconnect wallet' Settings page, the Remaining balance
  • On the page when monetization is active, the value that a user can enter to make a once-off payment/tip

[tselit]

Will mark this as cancelled - it's a duplicate of #113