[examples] Use MeshMatrixMass in hyperelastic examples

[hugtalbot]

Since users often copy paste examples, let's show good scene habits: when modeling volumetric, the MeshMatrixMass should be used instead.

I guess this will trigger the regression tests (but I need to recompile regression first, so I give the CI a chance :) )

[ci-depends-on https://github.com/SofaDefrost/ModelOrderReduction/pull/118]

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[hugtalbot]

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

[hugtalbot]

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

[sofabot]

[ci-depends-on] detected during build #3.

To unlock the merge button, you must

• Merge or close https://github.com/SofaDefrost/ModelOrderReduction/pull/118 _For this build, ModelOrderReduction/ExternalProjectConfig.cmake.in will be edited by builders with GIT_REPOSITORY https://github.com/SofaDefrost/ModelOrderReduction GITTAG 19bc3066274e000ee08512b075928a8a93250ad3