[ODESolver.Forward] Support mapped masses in EulerExplicitSolver

[alxbilger]

Based on #5997

Fixes #5999

Relevant commit: fdd47c0

[with-all-tests]
[ci-depends-on https://github.com/sofa-framework/ci/pull/78]

---

By submitting this pull request, I acknowledge that
I have read, understand, and agree SOFA Developer Certificate of Origin (DCO).

---

Reviewers will merge this pull-request only if

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

[fredroy]

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

[sofabot]

[ci-depends-on] detected during build #4.

To unlock the merge button, you must

• Merge or close Add missing plugin checks in python scenes ci#78
  For this build, the following CMake flags will be set
  -DCI_GIT_REPOSITORY='https://github.com/sofa-framework/ci'
  -DCI_GIT_TAG='353280b127a4ea17cb2dbf8ed019bc08b31d3a98'