Fix authorization status checker to check the last request before StopIteration

[rozgonik]

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What(What have you changed?)

Changed the order of checks.

Why(Why did you change it?)

Found a bug where the last GET response was not evaluated (but logged) before raising a StopIteration exception. Although the last response had a "valid" status, sewer still raised the exception.

This way the while loop does not terminate prematurely before checking the last request's status.

[codecov]

Codecov Report

Merging #148 into master will decrease coverage by 0.1%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #148      +/-   ##
==========================================
- Coverage   86.53%   86.42%   -0.11%     
==========================================
  Files          14       14              
  Lines         943      943              
==========================================
- Hits          816      815       -1     
- Misses        127      128       +1

Impacted Files	Coverage Δ
sewer/client.py	92.07% <100%> (-0.34%)	⬇️

[mmaney]

+1 on fixing the problem of throwing away the last result, which this should do.

-1 on the disguised counting loop that doubtless was the cause of this error in the first place. But that could be a refactoring for another time.

[komuw]

@mmaney are you happy with this PR?
If you are, you please add an approval. You can also go ahead and squash merge