Add toggle to hide private space entry point in All Apps

This change includes implementaion for below:
1. Add a preference inside private space settings page with a toggle switch to control hide/unhide
   private space entry in All Apps
2. Store the preference value in settingsprovider for persistence.

Bug: 302682054
Test: Manual
Change-Id: Ia1a56fc2c43550e23c00a61a5ce4742e42effcbe