fix(NcAppNavigation): also emit navigation-toggled on mobile change

[skjnldsv]

Since we keep and adjust the internal state and react to isMobile, we should advertise that state as we do for the normal open/close methods.

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.38%. Comparing base (6eec54e) to head (eb2be2c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8353      +/-   ##
==========================================
+ Coverage   52.37%   52.38%   +0.01%     
==========================================
  Files         104      104              
  Lines        3393     3394       +1     
  Branches      989      989              
==========================================
+ Hits         1777     1778       +1     
  Misses       1360     1360              
  Partials      256      256              

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[skjnldsv]

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