fix assertion in pi become request test

[simonLeary42]

unity-web-portal/test/functional/PiBecomeRequestTest.php

Line 13 in 969c0ad

$this->assertTrue($SQL->requestExists($USER->getUID()));

this doesn't actually assert the number of requests, only that the number is > 0. If the intention was to assert that there are no duplicates, then this is wrong.

[simonLeary42]

actually, there is no way currently to get the list of requests from a specific uid for a specific group. #244 will add getRequest, which asserts that there are no duplicates.