Fixed behaviour of at.subtensor.take when axis is None

[kc611]

A fix for #786

[codecov]

Codecov Report

Merging #787 (24d88b5) into main (77bcd68) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #787   +/-   ##
=======================================
  Coverage   78.41%   78.42%           
=======================================
  Files         152      152           
  Lines       47793    47786    -7     
  Branches    10884    10883    -1     
=======================================
- Hits        37479    37478    -1     
+ Misses       7766     7762    -4     
+ Partials     2548     2546    -2     

Impacted Files	Coverage Δ
aesara/tensor/subtensor.py	89.42% <100.00%> (-0.22%)	⬇️
aesara/tensor/math_opt.py	86.57% <0.00%> (+0.34%)	⬆️
aesara/misc/safe_asarray.py	69.23% <0.00%> (+15.38%)	⬆️