[PWGEM] PhotonMeson: Add basic QA for V0Photons

[mhemmer-cern]

• Add AreSelectedRunning function to V0PhotonCuts class, which allows the usage of EMButFlags once at the beginning of a process function instead of checking each V0 photon inside the pair loops.
• Add basic QA for V0Photons in the V0PhotonCuts class. To use it one must set the flag by using setDoQA(true) AND providing a pointer to the histogram registry of the main task. To initilize the histograms one needs to call fV0PhotonCut.addQAHistograms(&registry) in the init function of the task. For proper usage one needs to use AreSelectedRunning. It is possible to do it with the single V0 check function IsSelected(), however, not all histograms will be properly filled in that case.
• Fix basic QA inside EMCPhotonCuts

[alibuild]

Auto-approving on behalf of @mhemmer-cern.

[ktf]

The error on macOS seems to be genuine. Can you have a look?

[mhemmer-cern]

The error on macOS seems to be genuine. Can you have a look?

I just checked and it is not genuine, the variable is used:

O2Physics/EventFiltering/PWGEM/globalDimuonFilter.cxx

Line 313 in 26aa937

vec_min_chi2MatchMCHMFT.emplace_back(tupleIds_at_min_chi2mftmch);

It was modified last by this PR #14760

[ktf]

@mhemmer-cern actually it was and I fixed it in 9a2575e. I think the one you refer to is on a different line. Anyway, this is unrelated to this PR. Merging.

[mhemmer-cern]

@mhemmer-cern actually it was and I fixed it in 9a2575e. I think the one you refer to is on a different line. Anyway, this is unrelated to this PR. Merging.

Ah okay, then there must have been multiple declarations of that variable at some point before or something. Thanks for checking and merging!