UI cleanup for Customization Lock screen

This diff adjusts UI margins, colors and alignment

images:
https://drive.google.com/file/d/1_l3vLCsrj1dshaOzNj0gNAOx3Ric4k_G/view?usp=share_link&resourcekey=0-MlyTFpn1SKtDtmRBjFTsDQ
https://drive.google.com/file/d/1GcZaPdmUMppfIbxUmha2h4xr92-nMrHD/view?usp=share_link&resourcekey=0-ryP_h5Gr_2bPhGwjNwkepQ

Bug: 274926397
Test: manual
Change-Id: If9f1cb4f9e3cd802f17029c4e6c64eda082c502e