Change import path for RunningTaskInfo in IPip.aidl

This fixes sysui-studio's gradle build by importing RunningTaskInfo
directly instead of ActivityManager. Evidently gradle's aidl processor
can't handle that.

Fixes: 390634381
Flag: EXEMPT minor refactor
Test: gradle :WMShell:compileDebugAidl
Change-Id: Ida2cda2af4dc662987a3a5dbf2cf475ddded3165