simplify conservative mortars on the TreeMesh

[ranocha]

When looking at the mortar code, I noticed that we included some redundant computations on the TreeMesh.

@andrewwinters5000 @amrueda Since you worked on it, it would be great if you could review this change.

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.84%. Comparing base (a3fa435) to head (0d7332f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3062      +/-   ##
==========================================
- Coverage   96.84%   96.84%   -0.00%     
==========================================
  Files         636      636              
  Lines       49587    49575      -12     
==========================================
- Hits        48021    48009      -12     
  Misses       1566     1566              

Flag	Coverage Δ
unittests	96.84% <100.00%> (-<0.01%)	⬇️

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[JoshuaLampert]

LGTM, but a review by @amrueda or @andrewwinters5000 would be good.

[andrewwinters5000]

This looks good. Did you print out the conservation errors to double check that this did not influence anything in the run?

[amrueda]

Looks good to me!
Thanks for working on this. We discussed about improving the performance in #2134 (comment) and @ranocha created this issue back in the day: #2163

[ranocha]

Thanks for your reviews!

Concerning the conservation error:

julia> trixi_include("examples/tree_2d_dgsem/elixir_euler_sedov_blast_wave.jl", analysis_callback = AnalysisCallback(semi, interval = analysis_interval, extra_analysis_errors = (:conservation_error,)));
[...]
 |∑U - ∑U₀|:     6.07291994e-14   2.16840434e-17   4.84096270e-17   1.76247905e-15
[...]

julia> trixi_include("examples/tree_3d_dgsem/elixir_euler_sedov_blast_wave.jl", tspan = (0.0, 0.06), analysis_callback = AnalysisCallback(semi, interval = analysis_interval, extra_analysis_errors = (:conservation_error,)));
[...]
 |∑U - ∑U₀|:     2.14238349e-15   2.03287907e-20   3.52365706e-19   2.03287907e-19   3.71968081e-15
[...]