Remove head hydration workaround

Is your feature request related to a problem? Please describe.
Since Svelte 3.17.3 hydration now works with head elements. This removes the need for the noscript workaround.

Describe the solution you'd like
I will open PRs for sapper (#1067) and sapper-template (sveltejs/sapper-template#195)

Describe alternatives you've considered
Use the workaround in perpetuity since it works now and probably forever.

How important is this feature to you?
Not very; it is just a minor cleanup for the next time breaking changes to Sapper are up for consideration.

Additional context

• <svelte:head> creates duplicate elements on hydration svelte#1607
• fix hydrating header meta tags svelte#4082
• SSR should only render one <title> svelte#4250
• fix hydration of <title> svelte#4311