Use new color tokens in PeopleSpaceActivity

This CL fixes the color tokens of the PeopleSpaceActivity, and also
enables edge-to-edge so that we don't show the black navigation bar
background and the translucent status bar background.

See b/382448604#comment9 for before/after screenshots.

Bug: 382448604
Test: Manual, see b/382448604#comment9
Flag: EXEMPT bug fix & simple color change
Change-Id: I76a1b8950055c743234876aa6ef3d827e242a38f