Fix logic checking if suspension changed

Currently newSuspendParams is always non-null and oldSuspendParams is
always null because the wrong package was used to query the map
(suspended vs. suspending). As a result `changed` is always true.

Bug: 263464464
Test: atest SuspendPackageHelperTest
Test: atest CtsSuspendAppsTestCases:android.suspendapps.cts.SuspendPackagesTest
Change-Id: Ie70c008af4ecbcaeda4ac51014339dec004eb6b9