Gracefully handle Conversion Tracking failures. (#1796)

This PR makes it such that if Conversion Tracking is enabled and
the call to `ytag` fails, an `AnalyticsEvent` is still sent. We
simply leave out any `cookieData`. This was done in response to the
`ytag` asset being commonly blocked by various Ad-Blockers.

TEST=auto

Updated unit tests.

src/core/analytics/analyticsreporter.js

@@ -108,8 +108,7 @@ export default class AnalyticsReporter {
       ytag('optin', true);
       cookieData = ytag('yfpc', null);
     } else if (this._conversionTrackingEnabled) {
-      console.error('Tried to enable conversion tracking without including ytag');
-      return false;
+      console.error('Conversion Tracking is enabled without supplying ytag. Analytics event sent without Conversion Tracking info.');
     }
 
     if (!(event instanceof AnalyticsEvent)) {

tests/core/analytics/analyticsreporter.js

@@ -73,8 +73,8 @@ describe('reporting events', () => {
   it('logs a console error if opted in and ytag missing', () => {
     analyticsReporter.setConversionTrackingEnabled(true);
     const consoleErrorSpy = jest.spyOn(console, 'error');
-    expect(analyticsReporter.report(new AnalyticsEvent('thumbs_up'))).toBeFalsy();
-    expect(consoleErrorSpy).toHaveBeenLastCalledWith('Tried to enable conversion tracking without including ytag');
+    expect(analyticsReporter.report(new AnalyticsEvent('thumbs_up'))).toBeTruthy();
+    expect(consoleErrorSpy).toHaveBeenLastCalledWith('Conversion Tracking is enabled without supplying ytag. Analytics event sent without Conversion Tracking info.');
   });
 
   it('includes cookies if opted in and ytag present', () => {