The accumulated collected_facts was being update
with new facts _after_ filtering them. So only
facts that pass the filter would ever be passed
to other fact collectors.
For 'filter=ansible_service_mgr', even though it requires
the platform and distribution facts and even collects them,
they would get filtered out and never passed to the other
collectors that need them (service_mgr for ex).
Fix is just to add the unfiltered facts to collected_facts.
Adds unit tests for fact filter and collected_facts.
Fixes#32286
08f92a9f0f