MWPW-164470: Console error dynamic nav

[JasonHowellSlavin]

• Adds a check for the feds nav wrapper element before appending. Error only occured on gnav v1 uses.

Resolves: MWPW-164470

Test URLs:

• Before: https://main--milo--adobecom.aem.page/?martech=off
• After: https://console-error-dynamic-nav--milo--jasonhowellslavin.aem.page/?martech=off

To see that error is gone:
https://main--bacom-blog--adobecom.hlx.live/fr/blog/the-latest/deliver-winning-campaigns-at-speed-and-scale-with-adobe-genstudio-for-performance-marketing?milolibs=console-error-dynamic-nav

[aem-code-sync]

	Page	Scores	Audits	Google
📱	/?martech=off
🖥️	/?martech=off

[github-actions]

This pull request is not passing all required checks. Please see this discussion for information on how to get all checks passing. Inconsistent checks can be manually retried. If a test absolutely can not pass for a good reason, please add a comment with an explanation to the PR.