Add spruce lines for B2HPi0 with Dalitz pi0 decays

This MR add two new lines for

$B^+ \to K^+ \pi^0$

and

$B^+ \to \pi^+ \pi^0$

decays with

$\pi^0 \to e^+ e^- \gamma$

, based on the experience of reconstructing

$D^+ \to \pi^+ \pi^0$

decays in the Charm group. We've seen that the yield per inv fb increased by a factor of 10 between Run2 and Run3 for

$\pi^0 \to e^+ e^- \gamma$

decays, therefore it might now be worth including this final state for the

$B^+ \to h^+ \pi^0$

decays. The yield will be small due to the low efficiency, but the sample would be softer than the calorimeter

$\pi^0$

approach.

The lines has been run over all events in the sprucing testing snippet and the bandwidth is as follows:

Line	Eff	Rate
BuToKpPi0_Dalitz	2/371018 = 0.0000054	0.41 Hz
BuToPipPi0_Dalitz	3/371018 = 0.0000081	0.61 Hz

file_size = 171k

b/w (GB/s) = input rate (75.49 kHz for this HLT2 output file) x 0.171 (MB) / 371018

b/w (GB/s) = 0.000035 GB/s = 35 (KB/s)