Complete program execution on exceptions in async_mode=True

[jprafael]

Fixes and adds unit test for #206. Uses the proposed implementation with extra stuff to clean-up tasks after completion.

[jprafael]

@microsoft-github-policy-service agree company="Realm"

[slundberg]

Thanks! Will dig into this soon.

[codecov-commenter]

Codecov Report

Merging #231 (a46582d) into main (4651387) will decrease coverage by 0.11%. The diff coverage is 68.96%.

@@            Coverage Diff             @@
##             main     #231      +/-   ##
==========================================
- Coverage   67.74%   67.63%   -0.11%     
==========================================
  Files          54       54              
  Lines        2970     2985      +15     
==========================================
+ Hits         2012     2019       +7     
- Misses        958      966       +8     

Impacted Files	Coverage Δ
guidance/_program.py	56.61% <68.96%> (-0.42%)	:arrow_down:

[slundberg]

Thank you again for this PR @jprafael ! It looks good to me, and I am merging now.