RMX1971: A overlay: Allow more cached apps in the background

* Google has provisioned this on the Pixel 5 (RQ1A.201205.010) to utilize
  the 8 GB of RAM better, and I have also observed that a lightweight
  selection of apps was hitting the cached app limit before exhausting RAM
  on another device with 8 GB of RAM

  This shouldn't cause adverse effects on devices with less RAM (e.g. 4
  GB) as the low memory killer should kick in long before this limit on
  such devices