Remove usage of field_info_instances(), use EntityManager::getFieldDefinitions() instead

Sub-Issue from #2116363: [PP-1] Unified repository of field definitions (cache + API).

Look where that function is used, use EntityManager::getFieldDefinitions($entity_type, $bundle) instead.

If the bundle is not passed, you need to instead refactor the code to loop over the entity bundles instead. But start with the easy calls.