dev/core#2046 Fix Phone:add to be a pseudonym for Phone.create

dev/core#2046 Fix Phone:add to be a pseudonym for Phone.create

Per https://lab.civicrm.org/dev/core/-/issues/2046 we have discussed rationalising add vs create

In the case of phone making this change only affects one place - a place that currently has a
bug that relates specifically to the handling of is_primary & which is more solvable by
calling create with it's extra is_primary handling.

(the related bug is that the is_primary handling in Block::create is unreliable &
to mitigate that we are doing an additional 10 queries on every contact create - so
handling is_primary right in the first place helps address that)