Allow using sst.wri.org instead of https://www.googletagmanager.com (gtm)

[mariacha]

We've got this https://www.googletagmanager.com two places in our build:
https://github.com/wri/wri_sites/blob/main/modules/wri_common/js/wri_gtm.js

https://github.com/wri/wri_sites/blob/main/themes/custom/ts_wrin/templates/layout/html.html.twig#L67

These need to be swappable with the url sst.wri.org in both places. We can use Content Snippets to accomplish this:

Dev tasks

• Add a new content snippet for Analytics URL and make its default value https://www.googletagmanager.com. I'm assuming in the rest of these instructions that the machine name is analytics_url
• Update https://github.com/wri/wri_sites/blob/main/themes/custom/ts_wrin/templates/layout/html.html.twig#L67 to use {{ contentSnippets.analytics_url }}
• Pass that code snippet to the wri_common javascript drupal settings in this function: https://github.com/wri/wri_sites/blob/main/modules/wri_common/wri_common.module#L522
• Modify https://github.com/wri/wri_sites/blob/main/modules/wri_common/js/wri_gtm.js to use a drupalSettings.wri_common.analytics_url

this ticket is done when

• An administrator can update the "Analytics URL" content snippet to use https://sst.wri.org/gtm.js instead of https://www.googletagmanager.com.
• When they do this they see a call to https://sst.wri.org/gtm.js in the "Sources" tab of the browser console.
• If you view the page's source, the code under the " Google Tag Manager (noscript)" section contains https://sst.wri.org/ not https://www.googletagmanager.com
• If the administrator has not updated the Analytics URL value, they should continue to see calls to https://www.googletagmanager.com in both tests above.

How to test:

• On https://wri.org/ view source and confirm that there's an <iframe src="https://www.googletagmanager.com/ns.html?id=GTM-WGH5WB9" string.
• On https://wri.org/admin/content/content_snippets under "3rd Party" change the "Analytics URL" to https://sst.wri.org/
• Review https://wri.org/ again and verify the string is now `<iframe src="https://sst.wri.org/ns.html?id=GTM-WGH5WB9"
• Verify that the https://sst.wri.org value is seeing analytics from the develop site.

[mariacha]

This is ready for testing. The url for analytics can be updated at https://develop-wriflagship.pantheonsite.io/admin/content/content_snippets to https://sst.wri.org instead of https://www.googletagmanager.com and then we will want to verify that the analytics data is coming through from develop. @cpmadera passing to you to test out!