DEV: Reenable wizard test after fixing auto start for wizard qunit tests

`run-qunit.js` does not expect QUnit tests to start automatically but
our wizard QUnit setup did not respect the `qunit_disable_auto_start`
URL param. Hence, tests would start running automatically and when a
subsequent `QUnit.start()` function call is made, we ended up getting a
`QUnit.start cannot be called inside a test context.` error.

This error can be consistently reproduced in the `discourse:discourse_test` container but not in
the local development environment. I do not know why and did not feel
like it is important at this point in time to know why.

.github/workflows/tests.yml

@@ -158,11 +158,10 @@ jobs:
         run: QUNIT_EMBER_CLI=0 bin/rake qunit:test['1200000']
         timeout-minutes: 30
 
-      # Wizard tests are failing so disabled for now while we investigate
-      # - name: Wizard QUnit (Legacy)
-      #   if: matrix.build_type == 'frontend-legacy' && matrix.target == 'core'
-      #   run: QUNIT_EMBER_CLI=0 bin/rake qunit:test['600000','/wizard/qunit']
-      #   timeout-minutes: 10
+      - name: Wizard QUnit (Legacy)
+        if: matrix.build_type == 'frontend-legacy' && matrix.target == 'core'
+        run: QUNIT_EMBER_CLI=0 bin/rake qunit:test['600000','/wizard/qunit']
+        timeout-minutes: 10
 
       - name: Plugin QUnit (Legacy)
         if: matrix.build_type == 'frontend-legacy' && matrix.target == 'plugins'

app/assets/javascripts/wizard/test/test_helper.js

@@ -50,6 +50,13 @@ let createPretendServer = requirejs(
 ).default;
 
 let server;
+
+const queryParams = new URLSearchParams(window.location.search);
+
+if (queryParams.get("qunit_disable_auto_start") === "1") {
+  QUnit.config.autostart = false;
+}
+
 QUnit.testStart(function () {
   server = createPretendServer();
 });