fix bugs in issuer-server

[bnonni]

• fixing manifest filtering in issuer server
• adding trycatch to listen method
• fixing ms sleep
• create new method for sleeping

Closes #135

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 4.68750% with 61 lines in your changes missing coverage. Please review.

Project coverage is 47.36%. Comparing base (1d0fffc) to head (91680a9).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #136      +/-   ##
==========================================
- Coverage   47.45%   47.36%   -0.10%     
==========================================
  Files          62       61       -1     
  Lines        8682     8701      +19     
  Branches      286      291       +5     
==========================================
+ Hits         4120     4121       +1     
- Misses       4561     4579      +18     
  Partials        1        1              

Components	Coverage Δ
applicant	57.50% <34.80%> (-0.44%)	⬇️
common	43.59% <91.17%> (-0.37%)	⬇️
issuer	65.56% <47.13%> (-2.05%)	⬇️
server	59.87% <10.00%> (+2.17%)	⬆️