Update self.live variable when shutting down

[ansys-akarcher]

self.live was updated for LegacyGrpcServer but was not for GrpcServer.

This causes issues when shutting down and starting a new server immediately from the same variable.

Perhaps it may be better to add a mechanism upper in the class hierarchy in BaseServer so this variable gets updated for every child class ?

[codecov]

Codecov Report

Merging #857 (4c28b5e) into master (e3e15c0) will decrease coverage by 0.28%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #857      +/-   ##
==========================================
- Coverage   88.79%   88.52%   -0.28%     
==========================================
  Files          72       72              
  Lines        8220     8226       +6     
==========================================
- Hits         7299     7282      -17     
- Misses        921      944      +23     

[cbellot000]

@ansys-akarcher mayeb you could add the script you created to reproduce the bug as a unit test? they are in "/tests" folder