Fixes and improvements for Sign in with Apple

[Supereg]

Fixes and improvements for Sign in with Apple

♻️ Current situation & Problem

We recently tried to deploy Sign in with Apple to a live system and found several issues with the current implementation:

• Nonce generation found to be incompatible with Firebase (they are seemingly unable to handle some special characters)
• The .firebaseAccount(_:) modifier had issues injecting the AuthorizationController if there was a standard (e.g. notify or storage standard) injected into SpeziAccount
• Firebase account deletion requires a recent login.

This PR requires StanfordSpezi/SpeziAccount#31 to be merged.

⚙️ Release Notes

Fixes and improvements for Sign in with Apple.

📚 Documentation

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✅ Testing

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📝 Code of Conduct & Contributing Guidelines

By submitting creating this pull request, you agree to follow our Code of Conduct and Contributing Guidelines:

• I agree to follow the Code of Conduct and Contributing Guidelines.

[PSchmiedmayer]

Looks great 🚀

[codecov]

Codecov Report

Merging #20 (4e3c64f) into main (774c5e3) will decrease coverage by 0.54%.
The diff coverage is 50.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #20      +/-   ##
==========================================
- Coverage   59.14%   58.60%   -0.54%     
==========================================
  Files          17       17              
  Lines        1023     1053      +30     
==========================================
+ Hits          605      617      +12     
- Misses        418      436      +18     

Files	Coverage Δ
...ount/Account Services/FirebaseAccountService.swift	79.02% <100.00%> (-0.25%)	⬇️
...urces/SpeziFirebaseAccount/Utils/CryptoUtils.swift	95.00% <100.00%> (ø)
...Services/FirebaseEmailPasswordAccountService.swift	89.91% <83.34%> (-0.47%)	⬇️
...s/SpeziFirebaseAccount/Utils/FirebaseContext.swift	91.21% <50.00%> (-0.77%)	⬇️
...irebaseAccount/Views/FirebaseAccountModifier.swift	76.48% <53.85%> (-14.43%)	⬇️
...vices/FirebaseIdentityProviderAccountService.swift	30.71% <8.34%> (-0.94%)	⬇️

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[Supereg]

@PSchmiedmayer would you mind force merging? As we change things in the IdentityProvider, those diff changes are not covered.