dev/core#1705 APIv4 - Support pseudoconstant lookups

[colemanw]

Overview

Access field option lists via APIv4, works for both inputs and outputs (note that for APIv3 it only works for inputs).
See discussion at https://lab.civicrm.org/dev/core/-/issues/1705

Before

APIv4 could only input/output a field's raw value.

After

Adding a suffix beginning with : to a field name tells the api to convert the raw value to/from an option name or label. Currently supported suffixes are :name, :label, and :abbr (abbr applies to a handful of fields like state_province).

Technical Details

Tests include converting names of states based on the name of a country, which goes off the chainSelect metadata to tell the api which variables to replace first so e.g. we know the country_id before attempting to lookup the list of states.

[civibot]

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[eileenmcnaughton]

I did some light testing - utilising these within a test & it seems good. Lots of tests on this & existing code gives us flexibility to make these changes