Reset launch start times when removing a process

When removing an exiting process that is running foreground activities, clear the launch times for
the current windowing mode. When an app process is removed, activities from the process may be
relaunched. In the case of forceStopPackageLocked the activities are finished before any window
is drawn, and the launch time is not cleared. This will be incorrectly used to calculate launch time
for the next launched activity launched in the same windowing mode.

Bug: 80084651
Test: adb shell am start -W com.amazon.mShop.android.shopping/com.amazon.mShop.home.HomeActivity  && sleep 1 && adb shell am force-stop com.amazon.mShop.android.shopping
Change-Id: I2c4f0716c922baa1ad209b4ea1fa7ce366e0e108