[PS] Update PS icon.

Now we have a specific icon for Private Space in material icon lib (https://fonts.corp.google.com/icons?icon.query=private+space&icon.platform=android).
Figma: https://www.figma.com/file/K6bIIcG882EiJNjxvSWsFT/V%E2%80%A2-Private-Space?type=design&node-id=20135-133573&mode=design&t=hXFY1ODhROG362hc-0

Screenshot: https://screenshot.googleplex.com/4YwYyeupJWt2Lq5

Bug: 323434770
Test: unit + manual
Flag: aconfig com.google.android.apps.nexuslauncher.enable_inject_private_space_tile teamfood
Change-Id: I175c16d61ad9d263684c345622f17301eba4472d