Bug 1812910: Importer needs to use is_array() before count() in PHP 7.2

When we are wanting to check if there is an array to foreach loop over
and that array has at least one entry.

Currently we try to loop over entries by checking with just count() and we get error
- count(): Parameter must be an array or an object that implements Countable

behatnotneeded

Change-Id: I9accca2e97f415d5f9a2203b6fd984a41e95a4d0
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit 9b3e36e2)