Add meta tag to variable list in story ads

extensions/amp-story-auto-ads/0.1/story-ad-page.js

@@ -2,6 +2,7 @@ import {CommonSignals_Enum} from '#core/constants/common-signals';
 import {
   createElementWithAttributes,
   isJsonScriptTag,
+  iterateCursor,
   toggleAttribute,
 } from '#core/dom';
 import {elementByTag} from '#core/dom/query';
@@ -265,13 +266,24 @@ export class StoryAdPage {
           this.localizationService_
         ) || uiMetadata[A4AVarNames.CTA_TYPE];
 
-      // Store the cta-type as an accesible var for any further pings.
-      this.analytics_.then((analytics) =>
+      this.analytics_.then((analytics) => {
+        // Store the cta-type as an accesible var for any further pings.
         analytics.setVar(
           this.index_, // adIndex
           AnalyticsVars.CTA_TYPE,
           uiMetadata[A4AVarNames.CTA_TYPE]
-        )
+        );
+
+        // Set meta tag based variables.
+        const metaTags = (this.adDoc_ ?? this.adElement_).querySelectorAll('meta[name]');
+        iterateCursor(metaTags, (tag) => {
+          const {content, name} = tag;
+          // If the meta tag name is not alphanumberical, we would ignore it.
+          if (/^[a-zA-Z0-9\-_]+$/.test(name)) {
+            analytics.setVar(this.index_, `METATAG_AD_${name}`, content);
+          }
+        });
+      }
       );
 
       if (