Avoid hitting assert on XML export

[droidmonkey]

• Fixes KeepassXC crashes during export as *.xml #11365

Screenshots

Testing strategy

Type of change

• ✅ Bug fix (non-breaking change that fixes an issue)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.74%. Comparing base (0288188) to head (8f7e3fa).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #11367      +/-   ##
===========================================
+ Coverage    63.71%   63.74%   +0.03%     
===========================================
  Files          362      362              
  Lines        38001    38002       +1     
===========================================
+ Hits         24211    24222      +11     
+ Misses       13790    13780      -10     

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