Compilation warnings in PF tutorials

[rolalaro]

Fixing some compilation warnings in the PF tutorials when VISP_HAVE_DISPLAY is undefined

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 11 lines in your changes missing coverage. Please review.

Project coverage is 45.25%. Comparing base (c1624ea) to head (0a5ef8d).
Report is 13 commits behind head on master.

Files with missing lines	Patch %	Lines
tutorial/particle-filter/tutorial-pf.cpp	0.00%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1462      +/-   ##
==========================================
- Coverage   45.26%   45.25%   -0.01%     
==========================================
  Files        1121     1121              
  Lines      112131   112131              
  Branches    19077    19077              
==========================================
- Hits        50751    50750       -1     
- Misses      61380    61381       +1     

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[fspindle]

Thanks