build: re-enable console warning reporting in e2e tests (#4199)

Reverts commit a8b2575 and adds a webpack loader
to remove from bootstrap during the e2e-app build the :lang(en) selector that causes
the warning.

e2e-app/coverage.webpack.js

@@ -1,6 +1,16 @@
 module.exports = {
   module: {
     rules: [
+      {
+        test: /bootstrap\.css$/,
+        use: [
+          {
+            // This loader is used to remove from bootstrap during the e2e-app build
+            // the :lang(en) selector that causes a warning.
+            loader: require.resolve('./removeLangSelector'),
+          },
+        ],
+      },
       {
         test: /\.(js|ts)$/,
         use: [

e2e-app/removeLangSelector.js

@@ -0,0 +1,5 @@
+// This loader is used to remove from bootstrap during the e2e-app build
+// the :lang(en) selector that causes a warning.
+module.exports = function (file) {
+  return file.replace(/:lang\(en\)/g, "");
+};

e2e-app/setup.e2e-spec.ts

@@ -16,7 +16,7 @@ beforeAll(async() => {
   // Listen for all console events and handle errors
   test.page.on('console', async msg => {
     const type = msg.type();
-    if (type === 'error') {
+    if (type === 'error' || type === 'warning') {
       const output = ['Unexpected console error:'];
       for (const m of msg.args()) {
         output.push(await m.jsonValue());