test: drive the Settings screen in a browser and guard every popup element id (closes #229)

src/popup/views/settings.js

@@ -167,10 +167,7 @@ function renderWalletListSettings() {
 function show() {
     $("settings-rpc").value = state.rpcUrl;
     $("settings-blockscout").value = state.blockscoutUrl;
-    const networkSelect = $("settings-network");
-    if (networkSelect) {
-        networkSelect.value = state.networkId;
-    }
+    $("settings-network").value = state.networkId;
     renderTrackedTokens();
     renderSiteLists();
     renderWalletListSettings();
@@ -282,15 +279,13 @@ function init(ctx) {
     });
 
     const networkSelect = $("settings-network");
-    if (networkSelect) {
-        networkSelect.addEventListener("change", async () => {
-            const newId = networkSelect.value;
-            const net = await onChainSwitch(newId);
-            $("settings-rpc").value = state.rpcUrl;
-            $("settings-blockscout").value = state.blockscoutUrl;
-            showFlash("Switched to " + net.name + ".");
-        });
-    }
+    networkSelect.addEventListener("change", async () => {
+        const newId = networkSelect.value;
+        const net = await onChainSwitch(newId);
+        $("settings-rpc").value = state.rpcUrl;
+        $("settings-blockscout").value = state.blockscoutUrl;
+        showFlash("Switched to " + net.name + ".");
+    });
 
     $("settings-show-zero-balances").checked = state.showZeroBalanceTokens;
     $("settings-show-zero-balances").addEventListener("change", async () => {