Implementing unique session id

[germa89]

It should improve stability. Let's see.

Current situation

CICD fails because the docker image crashes quite frequently. We automatically reboot it (--restart always docker flag), but then the image comes with no data, clean.

But PyMAPDL is not aware that the database has been cleaned hence it request data which gives errors of different kind.

Approach

In this PR, I have implemented a session id unique for each PyMAPDL connection. Everytime it connects to a MAPDL session, using _connect method, it will fix a session ID. Also, when we issue mapdl.clear.

Every time we issue mapdl.run we check that the ids are the same in the client and in the server (only at testing). If they are not, I raise an issue which is catched by pytests, and re-run the test completely.

Opinion

I think the idea is good. But ideally we want to implement something that checks the health of the gRPC channel.
So far, I'm going to test this, and consider late:

• Use gRPC methods/functions for checking the channel health
• Expand id check to vgets.

Close #1915

[github-actions]

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• BUG
• NEW FEATURE
• Enhancement
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[codecov]

Codecov Report

Merging #1912 (734c1fa) into main (997e288) will increase coverage by 6.28%.
The diff coverage is 97.34%.

@@            Coverage Diff             @@
##             main    #1912      +/-   ##
==========================================
+ Coverage   80.82%   87.10%   +6.28%     
==========================================
  Files          44       45       +1     
  Lines        7489     8052     +563     
==========================================
+ Hits         6053     7014     +961     
+ Misses       1436     1038     -398