Bugfix: Fix mesh handle tests for 5 processes

[lenaploetzke]

Closes #2441

Describe your changes here:
The dg competence test for the mesh handle failed with 5 processes because the leaf neighbors of ghosts does not work as intended (See #2438). This test now works without using the neighbor of ghost elements.
The interpolation test failed because the mesh was partitioned before the data interpolation (implicit in the set_balance function because of the no_repartition=false flag). This cannot happen now.

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[codecov]

Codecov Report

❌ Patch coverage is 84.61538% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.65%. Comparing base (a65e38a) to head (9239a56).

Files with missing lines	Patch %	Lines
mesh_handle/mesh.hxx	84.61%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2440   +/-   ##
=======================================
  Coverage   82.65%   82.65%           
=======================================
  Files         132      132           
  Lines       21502    21515   +13     
=======================================
+ Hits        17772    17783   +11     
- Misses       3730     3732    +2     

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[spenke91]

Thanks for the fix! I just have two minor remarks and am pretty sure I will accept the next iteration :-)

[spenke91]

Is this maybe a candidate for throwing an error rather than a warning? I'd argue that if it othersise (a) crashes, it is better to have a clean abort here or (b) computes garbage, it's even more important to abort here. My experience is that warnings have a tendency to be overlooked by the users.

[lenaploetzke]

Hm i dont know. Isnt it in this case just fine to set the flag silently? Because this should always be the intend of the user in this case.

[spenke91]

Suggested change

	// TODO: If the neighbors of ghost work again, the following checks can be enables also for ghost large sides.
	// TODO: If the neighbors of ghost work again, the checks above can be enabled also for ghost large sides.

Or which checks do you mean?

[lenaploetzke]

Actually the checks below, we theoretically can just delete the break.