Fix incorrect daughter assignment in ParticleVertexFit
This MR addresses the issue raised in #355 (closed), where the current implementation of ParticleVertexFit assigns incorrect daughter particles to their mother particle when encountering composite daughters that lack valid vertex information. This results in incorrect decay chains for certain particle decays, such as B+ -> (chi_c1(1P) -> (J/psi(1S) -> mu+ mu-) gamma) K+ and B+ -> (J/psi(1S) -> mu+ mu-) (K*(892)+ -> K+ (pi0 -> gamma gamma)), which are converted to B+ -> (J/psi(1S) -> mu+ mu-) gamma K+ and B+ -> (J/psi(1S) -> mu+ mu-) K+, respectively.
Edited by Jiahui Zhuo