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/index.html

@@ -398,6 +398,7 @@
                     >
                         <option value="ETH">ETH</option>
                     </select>
+                    <div id="send-token-static" class="text-sm hidden"></div>
                 </div>
                 <div class="mb-2">
                     <label class="block mb-1">To</label>