Add an extra check for []CC in the decay descriptor of FunTuple

Addressing the issue #47 (comment 7219259)

This MR adds an extra check to issue a warning when a self-conjugated particle is marked with []CC.

To be tested with: Rec!3637 (merged) DaVinci!986 (merged)

Solve the issue: #47 (comment 7219259)

FYI: @pkoppenb @erodrigu @amathad