Fix wrong widget appearing in widget picker for tablet

The wrong widget would appear in tablets because we were finding the widgets by PackageUserKey title instead of comparing the PackageUserKey objects themselves.

Fix: 269160189
Test: Turn on LARGE_SCREEN_WIDGET_PICKER and verify that in landscape mode in tablet clicking the battery header shows the correct widget
Change-Id: I4f17ba057d9287fc83e3b1e0072cacf0eee3deef