EthicalAds: don't show ad on 404 pages (#430)

It seems the `isEnabled` method wasn't updated to accept the
`httpStatus` and that's why it wasn't working fine.

Now, the Ad won't be shown on pages like this one:
https://sphinx-rtd-theme.readthedocs.io/en/stable/notfound

Related #385
Closes #386

Author: humitos

dist/readthedocs-addons.js

@@ -343,9 +343,10 @@ export class EthicalAdsAddon extends AddonBase {
     this.loadEthicalAdLibrary();
   }
 
-  static isEnabled(config) {
+  static isEnabled(config, httpStatus) {
     return (
-      super.isEnabled(config) && config.addons.ethicalads.ad_free === false
+      super.isEnabled(config, httpStatus) &&
+      config.addons.ethicalads.ad_free === false
     );
   }
 }

dist/readthedocs-addons.js.map

@@ -61,4 +61,23 @@ describe("EthicalAds addon", () => {
       }),
     ).to.be.false;
   });
+
+  it("is disabled on 404 pages", () => {
+    expect(
+      EthicalAdsAddon.isEnabled(
+        {
+          addons: {
+            ethicalads: {
+              enabled: true,
+              ad_free: false,
+              campaign_types: ["community", "paid"],
+              keywords: ["docs", "data-science"],
+              publisher: "readthedocs",
+            },
+          },
+        },
+        404,
+      ),
+    ).to.be.false;
+  });
 });