Fix login flow by avoiding manual redirect policy on macOS client

[KarstenH792]

Summary

Fix login flow by changing redirect handling from ManualRedirectPolicy to NoLessSafeRedirectPolicy in src/libsync/accessmanager.cpp.

Problem

The current desktop client fails during account setup/login with a redirect-related error, while:

• server endpoints respond correctly
• curl tests succeed
• Nextcloud Desktop 4.0.2 works
• current versions fail

Fix

Replace:
QNetworkRequest::ManualRedirectPolicy

with:
QNetworkRequest::NoLessSafeRedirectPolicy

Result

With this change:

• Login Flow v2 completes successfully
• app password is returned
• DAV access works
• account setup succeeds

Additional context

This appears to be a regression compared to 4.0.2.

Related issue

Fixes #9794

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[KarstenH792]

Just checking if someone could take a quick look at this. The fix has been tested locally and resolves the login issue for me.

Happy to adjust if needed.