Replace send token dropdown with static display when token is locked

When sending from the address-token view, show the token symbol as
plain text instead of a disabled dropdown. ERC-20 tokens include an
etherscan link to the contract address. The dropdown is restored when
navigating back or entering send from other views.

src/popup/views/addressToken.js

@@ -338,7 +338,15 @@ function init(ctx) {
         } else {
             $("send-token").value = tokenId;
         }
-        $("send-token").disabled = true;
+        // Hide dropdown, show static token display
+        $("send-token").classList.add("hidden");
+        let staticHtml = escapeHtml(currentSymbol);
+        if (tokenId !== "ETH") {
+            const link = `https://etherscan.io/token/${tokenId}`;
+            staticHtml += ` <a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>`;
+        }
+        $("send-token-static").innerHTML = staticHtml;
+        $("send-token-static").classList.remove("hidden");
         updateSendBalance();
         showView("send");
     });