Fix private space settings cog margin

Inset on the lock button already exists, so in reality there are 4dp +
8dp margin from the settings button. To fix this, we can just reduce
8dp -> 4dp on the settings button.

bug: 331742915
Test: before: https://drive.google.com/file/d/1z6-U5eO5oM6h6uULNdmJciMCP_F33rDn/view?usp=sharing
after: https://drive.google.com/file/d/1yzCysJRaRKDp0kivhi6GWE83qsloh39U/view?usp=sharing
Flag: none
Change-Id: Iafb1101b8029398c139ba02f31a027db272132f3