[backend] Prevent retention rules to delete user individuals (#7787)

[SouadHadjiat]

Proposed changes

• add functions to a new data-consistency.Ts file : test if organization or individual can be deleted
• use these functions in middleware in internalDeleteById
• add a check in retention manager before deleting elements (so it won't try to delete user individuals for ex)
• cleanup code for organization deletion

Related issues

• 7787

Checklist

• [x] I consider the submitted work as finished
• [x] I tested the code for its functionality
• [x] 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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 68.08511% with 30 lines in your changes missing coverage. Please review.

Project coverage is 64.87%. Comparing base (d3a85de) to head (77feab8). Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...m/opencti-graphql/src/database/data-consistency.ts	77.94%	15 Missing :warning:
...rm/opencti-graphql/src/manager/retentionManager.ts	7.14%	13 Missing :warning:
...latform/opencti-graphql/src/database/middleware.js	75.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #9068 +/- ## ========================================== + Coverage 64.68% 64.87% +0.18% ========================================== Files 620 621 +1 Lines 59208 59303 +95 Branches 6520 6888 +368 ========================================== + Hits 38301 38472 +171 + Misses 20907 20831 -76 ```

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