"bp_xprofile_field_get_children" filter not called if no children present

[drkane]

The "bp_xprofile_field_get_children" filter is not called if there are no children found in the SQL query in row 750 of /buddypress/bp-xprofile/bp-xprofile-classes.php, in the "get_children" function. Instead false is immediately returned.

This means that if you want to add in children through a custom filter, there have to be dummy children present in the database.

A use case for this might be a field which allows you to select a country. Rather than add each individual country as a selection option, which would take a long time, we could instead add them through a filter in a plugin.

[boonebgorges]

In 8478:

Don't skip filter in BP_XProfile_Field::get_children() when no children are found

Even null results should go through the 'bp_xprofile_field_get_children'
filter, so that developers can add children dynamically.

Fixes #5692