[Fix] prob computation for parseq and vitstr models

[felixdittrich92]

This PR:

• fix prob comp for vitstr and parseq models

Any feedback is welcome 🤗

[codecov]

Codecov Report

Merging #1327 (0a226a8) into main (8245706) will increase coverage by 0.01%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1327      +/-   ##
==========================================
+ Coverage   95.75%   95.76%   +0.01%     
==========================================
  Files         154      154              
  Lines        6902     6902              
==========================================
+ Hits         6609     6610       +1     
+ Misses        293      292       -1     

Flag	Coverage Δ
unittests	95.76% <100.00%> (+0.01%)	⬆️

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

Files Changed	Coverage Δ
doctr/models/recognition/parseq/pytorch.py	97.16% <100.00%> (ø)
doctr/models/recognition/parseq/tensorflow.py	97.33% <100.00%> (ø)
doctr/models/recognition/vitstr/pytorch.py	100.00% <100.00%> (ø)
doctr/models/recognition/vitstr/tensorflow.py	97.61% <100.00%> (ø)

... and 2 files with indirect coverage changes