fix: mark `prettier` as an optional peer dependency #1860

Job	Run time
prepare	10m 49s
deployment	0s
prepare-win32	14m 3s
e2e	13m 16s
packages (@slicemachine/plugin-kit)	1m 55s
prettier	1m 32s
packages (@slicemachine/manager)	3m 58s
packages (@slicemachine/init)	2m 54s
packages (slice-machine-ui)	5m 46s
packages (start-slicemachine)	1m 37s
packages (@slicemachine/adapter-next)	2m 1s
packages (@slicemachine/adapter-nuxt)	2m 44s
packages (@slicemachine/adapter-nuxt2)	1m 59s
packages (@slicemachine/adapter-sveltekit)	2m 11s
packages-win32 (@slicemachine/plugin-kit)	5m 2s
packages-win32 (@slicemachine/manager)	9m 16s
packages-win32 (@slicemachine/init)	3m 54s
packages-win32 (slice-machine-ui)	6m 18s
packages-win32 (start-slicemachine)	2m 50s
packages-win32 (@slicemachine/adapter-next)	3m 53s
packages-win32 (@slicemachine/adapter-nuxt)	5m 8s
packages-win32 (@slicemachine/adapter-nuxt2)	5m 17s
packages-win32 (@slicemachine/adapter-sveltekit)	4m 6s
	1h 50m 29s

Provide feedback