fix: reintroduce root suspense fallback UI, with logging

[adamstankiewicz]

Description

• Reintroduces a parent <Suspense fallback={...}> in the component tree, but only conditionally rendered if a suspense error is caught by the newly introduced AppErrorBoundary. If a suspense fallback error is caught, the children are rendered again, but wrapped with Suspense and its fallback UI.
• Ensures suspended queries don't raise an error in the UI, no longer blocks the user journey, yet still logs an error for observability. Unfortunately, there's no trivial way to know which component/hook causes the suspense fallback without this error boundary approach.
• Updated relevant ADR.
• Upgrades @openedx/frontend-build to latest version.

For all changes

• Ensure adequate tests are in place (or reviewed existing tests cover changes)
• Ensure English strings are marked for translation. See documentation for more details.

Only if submitting a visual change

• Ensure to attach screenshots
• Ensure to have UX team confirm screenshots

[codecov]

Codecov Report

Attention: Patch coverage is 98.63014% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.60%. Comparing base (cf26017) to head (2881482).

Files with missing lines	Patch %	Lines
...mponents/search/popular-results/PopularResults.jsx	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1261      +/-   ##
==========================================
+ Coverage   89.47%   89.60%   +0.12%     
==========================================
  Files         404      406       +2     
  Lines        8741     8831      +90     
  Branches     2069     2067       -2     
==========================================
+ Hits         7821     7913      +92     
+ Misses        884      883       -1     
+ Partials       36       35       -1     

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