Extend VNC tests to prevent unstable coverage reports

[Martchus]

See https://progress.opensuse.org/issues/107254

[codecov]

Codecov Report

Merging #1962 (160c910) into master (0552534) will increase coverage by 0.11%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1962      +/-   ##
==========================================
+ Coverage   76.82%   76.94%   +0.11%     
==========================================
  Files          68       68              
  Lines        7095     7095              
==========================================
+ Hits         5451     5459       +8     
+ Misses       1644     1636       -8     

Impacted Files	Coverage Δ
consoles/VNC.pm	58.83% <0.00%> (+1.78%)	⬆️

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