Bug 1990981: Appending parameters correctly again to copy portfolios into group

There was an error in commit c8306324
on line 6453 (now line 6516)

Before:

!empty($params)

After

!$params

Should be

$params

Change-Id: I61779f9b3bd65ae802362e7c839b8e6a5c55b0bc
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>