Update private space setup string and loading screen title

This includes below changes based on the updated UX mocks:
- Add one more loading screen in setup flow
- Update feature intro text on Setup page
- To swap order of bullets on the setup intro screen
- Update "Private Space" to "private space" in setup flow screens

go/ss/7pVGBSPqezDek47.png
go/ss/ADLX8aXAAGgYQHD.png
go/ss/tYtrGypBgRuXM9V.png
go/ss/3zZfij6JDpudwYR.png
go/ss/BFtWegFZyTueQoT.png
Recording link - b/313654776#comment5

Bug: 313654776, 313882412, 313655290
Test: Verify title and text is same as UX flow
Change-Id: I6a985c4fd6ecbe8ddd11e36bf76a2a9cc8427ef5