fix(filterFilter): correctly handle deep expression objects

Previously, trying to use a deep expression object (i.e. an object whose
properties can be objects themselves) did not work correctly.
This commit refactors `filterFilter`, making it simpler and adding support
for filtering collections of arbitrarily deep objects.

Closes #9698

Signed-off-by: Georgios Kalpakas <g.kalpakas@hotmail.com>