Running the to the SoA format (T95965) when reading meshes means that none
of the changes from versioning would be applied first. This means important fixes like
rBf14995aba70a aren't applied first, so modifications could be done to invalid `CustomData`.
One option is to just move all changes to `CustomData` to mesh reading code, but that doesn't
align with the purpose of versioning, and adds unnecessary _permanent_ complexity. Instead,
just run the mesh versioning in the regular versioning file. Unlike other versioning, we won't put
this behind a subversion bump until 4.0.
Another option is structuring the change more like `ntreeUpdateAllNew`, but IMO that
doesn't fit well with the fact that this is just versioning where we also happen to write with
the old format for the time being.
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I noticed this problem when working on D15795.
To reproduce, check out `refactor-mesh-selection-generic` and run `ctest -R physics_cloth`.