Rewriting `AppRoutingContext` to avoid late URL state problems

[olemartinorg]

Description

When loading app-frontend, the would be a moment where AppRoutingContext would be out-of-sync with the real URL, causing the wrong thing to be rendered. For example, for a brief moment the 'you're on the wrong task' screen would be visible while progressing to the next task, only to be corrected a short moment later.

This was all caused by our AppRoutingContext. While it did solve re-rendering issues when irrelevant parts of the URL changed (such as the equivalent of useNavigationParam('instanceGuid') would re-render your component when the page key in the URL changed), the current (pre this PR) AppRoutingContext also has to wait until a useEffect() is triggered to update the store, which at that point can run selectors again and cause re-renders that corrects the UI.

This fix always reads the URL from window.location, but also has the useEffect() to update the state in order to force existing components to re-render when the relevant parts of the URL changes. The URL we store in zustand is never read.

EDIT: One problem uncovered in the tests was that DataModelsProvider now had outdated state, causing validation to happen on a non-writable data type in the custom-confirm.ts test. I fixes this as well, such that DataModelsProvider hangs on a <Loader /> while updating the state.

Related Issue(s)

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Verification/QA

• Manual functionality testing
  • [x] I have tested these changes manually
  • [ ] Creator of the original issue (or service owner) has been contacted for manual testing (or will be contacted when released in alpha)
  • [ ] No testing done/necessary
• Automated tests
  • [ ] Unit test(s) have been added/updated
  • [ ] Cypress E2E test(s) have been added/updated
  • [x] No automatic tests are needed here (no functional changes/additions)
  • [ ] I want someone to help me make some tests
• UU/WCAG (follow these guidelines until we have our own)
  • [ ] I have tested with a screen reader/keyboard navigation/automated wcag validator
  • [x] No testing done/necessary (no DOM/visual changes)
  • [ ] I want someone to help me perform accessibility testing
• User documentation @ altinn-studio-docs
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  • [x] No functionality has been changed/added, so no documentation is needed
  • [ ] I will do that later/have created an issue
• Support in Altinn Studio
  • [ ] Issue(s) created for support in Studio
  • [x] This change/feature does not require any changes to Altinn Studio
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[sonarcloud[bot]]

Quality Gate failed

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C Reliability Rating on New Code (required ≥ A)

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