ui: fix crash removing unsupported unicode chars

[Guts]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 16.45%. Comparing base (a4627ed) to head (7e97d1e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #207   +/-   ##
=======================================
  Coverage   16.45%   16.45%           
=======================================
  Files          31       31           
  Lines        2893     2893           
  Branches      297      297           
=======================================
  Hits          476      476           
  Misses       2397     2397           
  Partials       20       20           

Flag	Coverage Δ
unittests	16.45% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
dicogis/ui/misc_buttons.py	40.74% <ø> (ø)
dicogis/ui/tab_files.py	17.17% <ø> (ø)
dicogis/DicoGIS.py	0.00% <0.00%> (ø)