Save raw client username bytes if they are missing on successful pair verify

[bdraco]

We didn't used to save the raw bytes, but on the success case, iOS is going to send them to us again so we can save them if they are missing

Fixes #455

[codecov]

Codecov Report

Merging #458 (adafc3b) into dev (d9243b6) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              dev     #458      +/-   ##
==========================================
+ Coverage   92.26%   92.27%   +0.01%     
==========================================
  Files          20       20              
  Lines        2198     2201       +3     
  Branches      278      279       +1     
==========================================
+ Hits         2028     2031       +3     
  Misses        124      124              
  Partials       46       46              

Files	Coverage Δ
pyhap/hap_handler.py	86.28% <100.00%> (+0.10%)	⬆️

[bdraco]

@ikalchev Since I was in the area, I fixed I would solve this problem as well as it should allow people who are missing the bytes and have the username saved in the wrong case to avoid re-pairing and it should just start working