[Core,Helper] Prevent to create objects from unloaded plugins

[alxbilger]

When a plugin is loaded, the ObjectFactory is populated of Components from this plugin. However, when this plugin is "unloaded", it was still possible to create a component from the plugin. This PR detects that the ObjectFactory tries to instantiate an object that is from an unloaded plugin.
It is particularly useful when the initialization of the plugin fails (SofaCUDA for example). When the initialization fails, the plugin is unloaded.
A unit test is provided

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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).

[bakpaul]

To be discussed at the STC.

[alxbilger]

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

[hugtalbot]

else it looks good to me

[fredroy]

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

[fredroy]

Tests are fixed, ready then 👮