[backend] Improve application stopping time (#9740)

[aHenryJard]

Proposed changes

• enforce eslint "no floating promise" rule (backend only)
• fix all floating promises on existing code (backend only)

Note: api-test are passing locally (with 01|02) which is not the case on current master so I think it's solving part of end of tests issues, probably proiduction issues too.

Still this PR will requires deep tests.

Related issues

• closes Improve application stopping time #9740

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case (coverage and e2e)
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality

Further comments

[codecov]

Codecov Report

Attention: Patch coverage is 69.86301% with 22 lines in your changes missing coverage. Please review.

Project coverage is 65.39%. Comparing base (9276b5a) to head (d47d4eb).
Report is 10 commits behind head on master.

Files with missing lines	Patch %	Lines
...tform/opencti-graphql/src/graphql/sseMiddleware.js	0.00%	3 Missing ⚠️
...ti-platform/opencti-graphql/src/http/httpServer.js	0.00%	3 Missing ⚠️
...i-platform/opencti-graphql/src/config/providers.js	0.00%	2 Missing ⚠️
...platform/opencti-graphql/src/database/migration.js	0.00%	2 Missing ⚠️
...opencti-graphql/src/database/sessionStore-redis.js	33.33%	2 Missing ⚠️
...ti-platform/opencti-graphql/src/instrumentation.js	0.00%	2 Missing ⚠️
...rm/opencti-graphql/src/manager/ingestionManager.ts	0.00%	2 Missing ⚠️
opencti-platform/opencti-graphql/src/back.js	0.00%	1 Missing ⚠️
...ti-platform/opencti-graphql/src/database/engine.js	0.00%	1 Missing ⚠️
...pencti-graphql/src/database/sessionStore-memory.js	0.00%	1 Missing ⚠️
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9715      +/-   ##
==========================================
+ Coverage   65.26%   65.39%   +0.13%     
==========================================
  Files         630      630              
  Lines       60311    60434     +123     
  Branches     6774     6890     +116     
==========================================
+ Hits        39361    39522     +161     
+ Misses      20950    20912      -38     

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