Persist the actual simulated position of the ECAL hit rather than the cell center

[tvami]

I am updating ldmx-sw, here are the details.

What are the issues that this addresses?

Resolves https://github.com/LDMX-Software/ldmx-sw/issues/1484

But I'm only opening it as a draft first to see the effect using the CI tests

Check List

• [x] I successfully compiled ldmx-sw with my developments
• [ ] I ran my developments and the following shows that they are successful.

[tvami]

OK I think it's worth doing this. I'll also address https://github.com/LDMX-Software/ldmx-sw/issues/1482 in this PR next

[tvami]

I added the new plots: X

Y

Z

X/Y makes a lot of sense.

Z is what I believe is what's in https://github.com/LDMX-Software/ldmx-sw/issues/1490

[tvami]

@tomeichlersmith what do you think about the Z? Should I have https://github.com/LDMX-Software/ldmx-sw/issues/1490 takled in this PR too? Or maybe just open another PR... but then I dont know what to do with the weights

[tvami]

Or maybe just open another PR...

I think it's prob better to be in another PR provided that we dont have too much time in between the two PRs. Then I can easily compare these plots to show the changes

[tvami]

In the spirit that we are about to fix the issue for Z in the branch iss1490 I zoomed in in the Z axis in https://github.com/LDMX-Software/ldmx-sw/pull/1485/commits/d7d49895b0732140fb83fe97f1a2d030b417dc29