[Simulation] Change LoadFromMemory signature to remove unused parameter Size

[epernod]

Method LoadFromMemory to load an XML as a string is taking a parameter size which is unused and generate conversion warnings in tests.

• Add method depreciation
• Update all tests compiled in my setup.

---

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).

[epernod]

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