Bug 23012: (QA follow-up) Combine method to get both values

Bug 23012: (QA follow-up) Combine method to get both values

The code for get_processingreturn_policy was very similar to
get_lostreturn_policy. Combining the two methods allows for use of
get_effective_rules which uses get_effective_rule_value which is cached.
This should reduce lines of code and improve performance

Tests updated and adjusted as well

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>