Set zoom level min limit when zoom to full page

[kbengs]

This will prevent exception if window is resized to smallest possible
and user tries to zoom to full page.

[codecov-io]

Codecov Report

Merging #429 (eb3e03b) into main (0921e5e) will decrease coverage by 0.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main     #429      +/-   ##
==========================================
- Coverage   72.03%   72.01%   -0.02%     
==========================================
  Files          10       10              
  Lines        2657     2659       +2     
==========================================
+ Hits         1914     1915       +1     
- Misses        743      744       +1     

Impacted Files	Coverage Δ
pdfarranger/pdfarranger.py	66.49% <66.66%> (-0.03%)	⬇️

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