west.yml: update Zephyr to c50777a84311 #705

Job	Run time
build-windows (imx8 imx8x imx8m imx8ulp)	8m 43s
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	6m 12s
build-windows (mtl)	7m 3s
manifest-check	45s
build-linux (mnfst, mtl)	4m 42s
build-windows (tgl tgl-h)	7m 24s
build-linux (mnfst, lnl)	4m 36s
LP64-WIP	3m 56s
build-windows (-d, mtl)	7m 11s
build-linux (mnfst, tgl tgl-h)	5m 13s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	5m 53s
build-linux (zmain, mtl)	4m 18s
build-linux (zmain, lnl)	4m 14s
build-linux (zmain, tgl tgl-h)	5m 18s
build-linux (-d, mnfst, mtl)	4m 26s
build-linux (mnfst, --all)	12m 8s
compare-linux-win	23s
	1h 32m 25s

Provide feedback