[FIX] owdistancemap: Fix an implicit float->int conversion error

[ales-erjavec]

Raises error on Python 3.10

Issue

Distance Map raises an error on Python 3.10 when setting any Annotations that are not None

----------------------------- TypeError Exception -----------------------------
Traceback (most recent call last):
  File "/home/ales/devel/orange3/Orange/widgets/unsupervised/owdistancemap.py", line 695, in resizeEvent
    self._updateFontSize()
  File "/home/ales/devel/orange3/Orange/widgets/unsupervised/owdistancemap.py", line 713, in _updateFontSize
    fontsize = min(self._point_size(lineheight), maxfontsize)
  File "/home/ales/devel/orange3/Orange/widgets/unsupervised/owdistancemap.py", line 721, in _point_size
    font.setPointSize(height)
TypeError: setPointSize(self, int): argument 1 has unexpected type 'float'
-------------------------------------------------------------------------------

Description of changes

Fix an implicit float->int conversion error

Includes

• Code changes
• Tests
• Documentation

[codecov]

Codecov Report

Merging #5998 (061d973) into master (17a242f) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #5998      +/-   ##
==========================================
+ Coverage   86.46%   86.56%   +0.10%     
==========================================
  Files         315      315              
  Lines       67248    67251       +3     
==========================================
+ Hits        58146    58217      +71     
+ Misses       9102     9034      -68