[backend] Fix on get exercise details to have better performance

[Dimfacion]

Proposed changes

• Fix on get exercise details to have better performance

Related issues

Checklist

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

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0.55556% with 179 lines in your changes missing coverage. Please review.

Project coverage is 25.80%. Comparing base (c7039b5) to head (56c7a72).

Files	Patch %	Lines
...io/openbas/rest/exercise/form/ExerciseDetails.java	0.00%	101 Missing :warning:
...ain/java/io/openbas/rest/exercise/ExerciseApi.java	1.33%	74 Missing :warning:
.../io/openbas/rest/exercise/form/ExerciseSimple.java	0.00%	2 Missing :warning:
...io/openbas/scheduler/jobs/InjectsExecutionJob.java	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1059 +/- ## ============================================ - Coverage 26.58% 25.80% -0.79% + Complexity 1041 1012 -29 ============================================ Files 460 461 +1 Lines 10686 10785 +99 Branches 515 526 +11 ============================================ - Hits 2841 2783 -58 - Misses 7779 7936 +157 Partials 66 66 ```

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