Add translations keys for multi-transaction signing UI

Add translation keys for multi-tx heading, transaction count, total
fees label, and "Confirm transactions".

Author: Mathéo

src/translations/en.json

@@ -84,8 +84,11 @@
     "sign-tx-heading-tx": "Confirm Transaction",
     "sign-tx-heading-checkout": "Verify Payment",
     "sign-tx-heading-cashlink": "Create a Cashlink",
+    "sign-tx-heading-multi": "Confirm Transactions",
     "sign-tx-fee": "fee",
     "sign-tx-cancel-payment": "Cancel payment",
+    "sign-tx-multi-count": "{count} transactions",
+    "sign-tx-multi-total-fees": "total fees",
 
     "sign-multisig-tx-heading-tx": "Approve Multisig Transaction",
     "sign-multisig-tx-approving-as-name-with-account": "Approving as {userName} with {accountName}",
@@ -115,6 +118,7 @@
     "passwordbox-confirm": "Confirm",
     "passwordbox-log-out": "Confirm logout",
     "passwordbox-confirm-tx": "Confirm transaction",
+    "passwordbox-confirm-txs": "Confirm transactions",
     "passwordbox-create-cashlink": "Create cashlink",
     "passwordbox-confirm-create": "Create account",
     "passwordbox-confirm-log-in": "Log in",