[tmva][sofie] Delete copying of SOFIE-emitted session classes

[guitargeek]

Some data members of the session classes are pointers to memory owned by the session class, so the session can't be trivially copied.

Instead of implementing a proper copy constructor and copy assignment, just delete them because they are also not needed.

[github-actions]

Test Results

    24 files      24 suites   3d 22h 42m 43s ⏱️
 3 883 tests  3 878 ✅ 0 💤  5 ❌
83 075 runs  83 040 ✅ 0 💤 35 ❌

For more details on these failures, see this check.

Results for commit 6c0a38e.

[silverweed]

Actually, is the class even allowed to move, since it has self-referencing pointers?

Probably yes, but the move ctor cannot just be the default one, otherwise the moved pointer still points to the old object, no?

[guitargeek]

The members of the class are std::vectors and raw pointers that point into specific places of the vectors. If the vectors are moved, the memory stays at the same place I think. So should be fine.

I'll clarify that in the inline comments because indeed if the self-referencing pointer points to this that would be a problem

[silverweed]

The members of the class are std::vectors and raw pointers that point into specific places of the vectors

Why use pointers at all btw? Why not just store indices, which would even make the class copyable?

[guitargeek]

Good idea! This would be a bigger refactor though. Maybe let's for now focus on the minimal fix #23624 so we can resolve the CI failures.