[SofaBaseTopology][SofaExporter] Fix failing tests due to changes in topology

[hugtalbot]

Fix tests further to #1323

• SofaExporter_test was expecting to export Hexa while option computeHexa was false in RGrid
• RegularGridTopology_test was expecting the wrong number of edges since the computation is now under the condition whether the triangles are used or not to compute the edges

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This PR:

• builds with SUCCESS for all platforms on the CI.
• does not generate new warnings.
• does not generate new unit test failures.
• does not generate new scene test failures.
• does not break API compatibility.
• is more than 1 week old (or has fast-merge label).

Reviewers will merge only if all these checks are true.

[hugtalbot]

did you apply the clang auto-format or are these manual changes? @guparan

[guparan]

I quickly applied a simple formatter online and finished manually. This file was a mess.

[epernod]

[ci-build][with-all-tests]

[hugtalbot]

Is everything good for you then @epernod ?

[epernod]

you didn't answer my last question regarding change of name: TEST_P(RegularGridTopology_test, regularGridSizeComputeEdgeFromTriangle)

[hugtalbot]

@epernod I needed to have two different names for the same test:

• one when edges are computed from an existing triangle topology
• and one when edges are computed from hexa.