As per T2167, a copy to clipboard icon is added next to the OP_RETURN message so users can easily extract the contents.

Dev notes:

• Borrowed the draft propagation logic from D10826 to minimise rework - will rebase to the final propagation logic in D10826 once that lands first.
• The buffer string conversion logic in Tx.js' handleCopyMsgToClipboard function will be backed out once D10821 lands where only strings will be returned to the frontend.

Dependencies: D10826, D10821.

• npm test and navigate to the Wallet screen
• click on the copy icon next to a normal inbound Cashtab message and ensure the message contents are copied to clipboard and a generic notification is displayed.
• repeat the above for a normal outbound cashtab message
• repeat the above for an encrypted inbound cashtab message
• repeat the above for a normal inbound cashtab message at the 160 char limit
• repeat the above for a normal inbound cashtab message with special characters
• repeat the above for a normal inbound Electrum message
• click on 'Reply To Message' link and ensure no regression from this diff
• click on anywhere else on the TxWrapper and ensure no regression (i.e. still takes you to the explorer)
• send a new transaction to the wallet and ensure no regression with Tx History display logic