Update the colors of the tabs of work profile pagination

Update the tab colors based on the discussion in the bug and the
design mock.
Rename the color/all_apps_tab_bg to
color/all_apps_tab_background_selected to make the usage of the color
explicit.
(Confirmed it's only used for the color of the selected tab)

Bug: 189488670
Test: Visual inspection
Change-Id: I6ac38f71a8dd8852e1ab2e70f2f8434e9101daa1