fix: youtube race condition when GTM loads

[viadanna]

Description

The changes fix an issue with YouTube videos when Google Analytics is used. It prevents the video XBlock from properly loading YouTube videos.

It's caused by a race condition, in which both Open edX and GTM implement onYouTubeIframeAPIReady and run already existing implementations of this callback.

The issue arises when GTM overwrites it, as the callback implemented by Open edX expects a resolve() attribute that isn't implemented by GTM. This change ensures the original global is used by Open edX so it's never overwritten.

Testing instructions

Testing

1. Set up a devstack/instance with this branch and Google Analytics.
2. Navigate to a Unit containing a YouTube video and open your browser Development Tools.
3. Add the following breakpoint:
   
4. Reload the page and wait a couple of seconds before pressing F8 to continue running. This ensures that onYouTubeIframeAPIReady is overwritten by GTM.
5. Make sure the YouTube video loads correctly.
6. Disable the breakpoint and reload, again making sure the Youtube video loads when the callback set by Open edX is used.

Deadline

"None"

Other information

• https://developers.google.com/youtube/iframe_api_reference#Requirements

[openedx-webhooks]

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[mphilbrick211]

Hi @viadanna! Just flagging that there are some failing checks. Would you mind taking a look?

[viadanna]

Sure thing @mphilbrick211

[viadanna]

@mphilbrick211 There was a problem with the testing infrastructure, can you restart the unit-tests workflow?

[mphilbrick211]

Hi @viadanna! I'm looking into this for you.

[mphilbrick211]

Hi @viadanna! All looks OK now, so I'm marking this as ready for review.

[pomegranited]

Hi @viadanna @mphilbrick211 may I review/merge this PR as CC?

[viadanna]

Sure thing @pomegranited

[pomegranited]

@viadanna Which Jira ticket is this issue for?

[viadanna]

@pomegranited BB-7904 (private)

[pomegranited]

👍

I wasn't able to reproduce the actual race condition (on master), but race conditions can be hard to reproduce. Instead, I verified that this change does not break videos or GA4 analytics.

• I tested this using the PR test instructions.
• I read through the code.
• I checked for accessibility issues N/A
• Includes documentation N/A
• User-facing strings are extracted for translation N/A

[ArturGaspar]

👍

• I tested this: I checked that GTM is being loaded with the key provided in settings, and tested according to the PR instructions and checked that the video works with or without setting the breakpoint
• I read through the code
• I checked for accessibility issues - N/A
• Includes documentation - N/A
• I made sure any change in configuration variables is reflected in the corresponding client's configuration-secure repository. - N/A

[openedx-webhooks]

@viadanna 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX staging environment in preparation for a release to production.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.