[REF] Move the storing of custom data into the add function rather th…

[seamuslee001]

…an in the create function so it is processed before the post hook

Overview

This moves the saving of custom data to within the add() function from the create() function so that any custom data that is processed with the original create is processed before any custom data processing in post hooks. This is similar to #16061

Before

Submitted custom data processed after post hook invocation

After

Submitted custom data is processed before post hook is invoked

ping @eileenmcnaughton

[civibot]

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[eileenmcnaughton]

@seamuslee001 I've been wondering why we continue to have an add function ... I think originally the idea was that add would be different to create but there is no consistency & I was thinking we should fold add back in to create

[seamuslee001]

@eileenmcnaughton yeh i'm not sure either but there maybe something in APIv3 that assumes there will be an add maybe i dunno

[eileenmcnaughton]

No, apiv3 prefers create & falls back on add if it has to

[mattwire]

@seamuslee001 I'm sure this has come up before and just not got around to change..