If a REC in a Library is ill-structured, the RPL creation in a Project fails silently

[flatombe]

Due to manual user operation, or in case of bugs like issue #2882, users can sometimes end up with ill-structured RECs in a Capella Library.
There is no validation to report about issues in the REC.
Then when trying to instantiate a corresponding RPL in a Capella Project, the UI makes it seem that everything worked as expected, but in reality a RollbackException got thrown.

Reproduction:

• Create a Capella Library
• Create two LogicalFunctions LF1 and LF2 connected by a FunctionalExchange FE1 through FIP1 and FOP1
• Create a REC containing only LF1, LF2 and FE1 (Note: the UI tries to add them by default, but by manual user operation or due to issue org.polarsys.capella.core.re.project.ReProjectScope ignores elements with a set ProgressStatus #2882, it can happen organically that we end up in this situation)
• Create a Capella Project and reference the library
• Create a RPL of the REC defined above => Nothing happens: the session is not dirty (and the model not modified), no log, etc. Underneath, a RollbackException has been thrown.
• Bonus: create a RPL in the Library itself => the RPL gets created and the REC gets automatically enriched with FIP1 and FOP1

Fix:

• Maybe add validation rules on RECs to warn of missing key elements
• Provide some user feedback when the RPL instantiation fails (log an error, display an error message dialog)
• Provide some user feedback when their REC gets automatically modified (log an info, maybe display a confirmation dialog beforehand)

(Capella 6.1.0 / Windows 11)