[AA+] Add QueryLength to DeviceSearchResultContainer. am: 43b1d40918

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/13486574

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ifc935c178457f9e614134f2f36ae6892b5476c70