[REF] dev/core#2790 deprecate preProcessSingle

[eileenmcnaughton]

Overview

[REF] dev/core#2790 deprecate preProcessSingle

Before

Function is on another class, function name doesn't give much information about what it is doing so it just adds complexity

After

Code brought 'back into the fold'

Technical Details

This is only called from here & is short & can just be part of the main function.

Comments

@demeritcowboy another fairly simple one

[civibot]

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