Update iconloaderlib min_sdk_version to 26. am: e543049272 am: 235562ce78 am: 80b5920bf7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/libs/systemui/+/15602014

Change-Id: I1d8159fed8e9b0f17790e1a76dbb2c31263f8397
tree: 5b4c37764e65ff784b2c0a7f4dbef3f46635eaef
  1. iconloaderlib/
  2. searchuilib/