feat(css-map): add header 1.2.49 classnames

[ohitstom]

My working / reasoning for each classname is below if you care to read it

original -> surrounding identifier -> new

.main-entityHeader-backgroundColor -> .main-entityHeader-container > div:nth-child(1),  .main-entityHeader-container > div:nth-child(2) !! first classname only, second is  "main-entityHeader-overlay" !! -> .PeLrpasyfBW8ql_bmoAi  

.main-actionBarBackground-background -> .playlist-playlist-playlistContent > div:first-of-type -> .PkOz5g82CaoKk1J3GX0e

.main-entityHeader-background -> .comfy-banner-frame + div > div !! the first classname on both divs the second is "main-entityHeader-gradient" for the first div and "main-entityHeader-overlay" for the second !! -> i_kMOBXfnweAkv8s97Yc

main-entityHeader-gradient -> .sv5suqIPUwjgUF_BzM41

main-entityHeader-overlay -> .I0bVSxvqA3rm5HvciMap

.main-entityHeader-overlay -> .main-entityHeader-container > div:nth-child(2) !! second classname !! -> .yhlH4Dsjqw56Z58EOwvQ

[sceriffoo]

yo how do i apply this update?